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Sample records for polymer-microfabricated silicon nanoporous

  1. Performance improvement of silicon solar cells by nanoporous silicon coating

    Directory of Open Access Journals (Sweden)

    Dzhafarov T. D.

    2012-04-01

    Full Text Available In the present paper the method is shown to improve the photovoltaic parameters of screen-printed silicon solar cells by nanoporous silicon film formation on the frontal surface of the cell using the electrochemical etching. The possible mechanisms responsible for observed improvement of silicon solar cell performance are discussed.

  2. Thermal carbonization of nanoporous silicon

    Indian Academy of Sciences (India)

    An interesting phenomenon is observed while carrying out thermal carbonization of porous silicon (PS) with an aim to arrest the natural surface degradation, and it is a burning issue for PS-based device applications. A tubular carbon structure has been observed on the PS surface. Raman, Fourier transform infrared ...

  3. Fabrication and Modification of Nanoporous Silicon Particles

    Science.gov (United States)

    Ferrari, Mauro; Liu, Xuewu

    2010-01-01

    Silicon-based nanoporous particles as biodegradable drug carriers are advantageous in permeation, controlled release, and targeting. The use of biodegradable nanoporous silicon and silicon dioxide, with proper surface treatments, allows sustained drug release within the target site over a period of days, or even weeks, due to selective surface coating. A variety of surface treatment protocols are available for silicon-based particles to be stabilized, functionalized, or modified as required. Coated polyethylene glycol (PEG) chains showed the effective depression of both plasma protein adsorption and cell attachment to the modified surfaces, as well as the advantage of long circulating. Porous silicon particles are micromachined by lithography. Compared to the synthesis route of the nanomaterials, the advantages include: (1) the capability to make different shapes, not only spherical particles but also square, rectangular, or ellipse cross sections, etc.; (2) the capability for very precise dimension control; (3) the capacity for porosity and pore profile control; and (4) allowance of complex surface modification. The particle patterns as small as 60 nm can be fabricated using the state-of-the-art photolithography. The pores in silicon can be fabricated by exposing the silicon in an HF/ethanol solution and then subjecting the pores to an electrical current. The size and shape of the pores inside silicon can be adjusted by the doping of the silicon, electrical current application, the composition of the electrolyte solution, and etching time. The surface of the silicon particles can be modified by many means to provide targeted delivery and on-site permanence for extended release. Multiple active agents can be co-loaded into the particles. Because the surface modification of particles can be done on wafers before the mechanical release, asymmetrical surface modification is feasible. Starting from silicon wafers, a treatment, such as KOH dipping or reactive ion

  4. Effects of pore design on mechanical properties of nanoporous silicon

    International Nuclear Information System (INIS)

    Winter, Nicholas; Becton, Matthew; Zhang, Liuyang; Wang, Xianqiao

    2017-01-01

    Nanoporous silicon has been emerging as a powerful building block for next-generation sensors, catalysts, transistors, and tissue scaffolds. The capability to design novel devices with desired mechanical properties is paramount to their reliability and serviceability. In order to bring further resolution to the highly variable mechanical characteristics of nanoporous silicon, here we perform molecular dynamics simulations to study the effects of ligament thickness, relative density, and pore geometry/orientation on the mechanical properties of nanoporous silicon, thereby determining its Young's modulus, ultimate strength, and toughness as well as the scaling laws versus the features of interior ligaments. Results show that pore shape and pattern dictate stress accumulation inside the designed structure, leading to the corresponding failure signature, such as stretching-dominated, bending-dominated, or stochastic failure signatures, in nanoporous silicon. The nanostructure of the material is also seen to drive or mute size effects such as “smaller is stronger” and “smaller is ductile”. This investigation provides useful insight into the behavior of nanoporous silicon and how one might leverage its promising applications. - Graphical abstract: Molecular dynamics simulations are performed to study the effects of ligament thickness, relative density, and pore geometry/orientation on the mechanical properties of nanoporous silicon, thereby determining its Young's modulus, ultimate strength, and toughness as well as the scaling trends versus the features of interior ligaments.

  5. Diffusive Silicon Nanopore Membranes for Hemodialysis Applications.

    Directory of Open Access Journals (Sweden)

    Steven Kim

    Full Text Available Hemodialysis using hollow-fiber membranes provides life-sustaining treatment for nearly 2 million patients worldwide with end stage renal disease (ESRD. However, patients on hemodialysis have worse long-term outcomes compared to kidney transplant or other chronic illnesses. Additionally, the underlying membrane technology of polymer hollow-fiber membranes has not fundamentally changed in over four decades. Therefore, we have proposed a fundamentally different approach using microelectromechanical systems (MEMS fabrication techniques to create thin-flat sheets of silicon-based membranes for implantable or portable hemodialysis applications. The silicon nanopore membranes (SNM have biomimetic slit-pore geometry and uniform pores size distribution that allow for exceptional permeability and selectivity. A quantitative diffusion model identified structural limits to diffusive solute transport and motivated a new microfabrication technique to create SNM with enhanced diffusive transport. We performed in vitro testing and extracorporeal testing in pigs on prototype membranes with an effective surface area of 2.52 cm2 and 2.02 cm2, respectively. The diffusive clearance was a two-fold improvement in with the new microfabrication technique and was consistent with our mathematical model. These results establish the feasibility of using SNM for hemodialysis applications with additional scale-up.

  6. Diffusive Silicon Nanopore Membranes for Hemodialysis Applications

    Science.gov (United States)

    Kim, Steven; Feinberg, Benjamin; Kant, Rishi; Chui, Benjamin; Goldman, Ken; Park, Jaehyun; Moses, Willieford; Blaha, Charles; Iqbal, Zohora; Chow, Clarence; Wright, Nathan; Fissell, William H.; Zydney, Andrew; Roy, Shuvo

    2016-01-01

    Hemodialysis using hollow-fiber membranes provides life-sustaining treatment for nearly 2 million patients worldwide with end stage renal disease (ESRD). However, patients on hemodialysis have worse long-term outcomes compared to kidney transplant or other chronic illnesses. Additionally, the underlying membrane technology of polymer hollow-fiber membranes has not fundamentally changed in over four decades. Therefore, we have proposed a fundamentally different approach using microelectromechanical systems (MEMS) fabrication techniques to create thin-flat sheets of silicon-based membranes for implantable or portable hemodialysis applications. The silicon nanopore membranes (SNM) have biomimetic slit-pore geometry and uniform pores size distribution that allow for exceptional permeability and selectivity. A quantitative diffusion model identified structural limits to diffusive solute transport and motivated a new microfabrication technique to create SNM with enhanced diffusive transport. We performed in vitro testing and extracorporeal testing in pigs on prototype membranes with an effective surface area of 2.52 cm2 and 2.02 cm2, respectively. The diffusive clearance was a two-fold improvement in with the new microfabrication technique and was consistent with our mathematical model. These results establish the feasibility of using SNM for hemodialysis applications with additional scale-up. PMID:27438878

  7. Silicon deposition in nanopores using a liquid precursor

    Science.gov (United States)

    Masuda, Takashi; Tatsuda, Narihito; Yano, Kazuhisa; Shimoda, Tatsuya

    2016-11-01

    Techniques for depositing silicon into nanosized spaces are vital for the further scaling down of next-generation devices in the semiconductor industry. In this study, we filled silicon into 3.5-nm-diameter nanopores with an aspect ratio of 70 by exploiting thermodynamic behaviour based on the van der Waals energy of vaporized cyclopentasilane (CPS). We originally synthesized CPS as a liquid precursor for semiconducting silicon. Here we used CPS as a gas source in thermal chemical vapour deposition under atmospheric pressure because vaporized CPS can fill nanopores spontaneously. Our estimation of the free energy of CPS based on Lifshitz van der Waals theory clarified the filling mechanism, where CPS vapour in the nanopores readily undergoes capillary condensation because of its large molar volume compared to those of other vapours such as water, toluene, silane, and disilane. Consequently, a liquid-specific feature was observed during the deposition process; specifically, condensed CPS penetrated into the nanopores spontaneously via capillary force. The CPS that filled the nanopores was then transformed into solid silicon by thermal decomposition at 400 °C. The developed method is expected to be used as a nanoscale silicon filling technology, which is critical for the fabrication of future quantum scale silicon devices.

  8. Electrically tunable solid-state silicon nanopore ion filter

    Directory of Open Access Journals (Sweden)

    Gracheva Maria

    2006-01-01

    Full Text Available AbstractWe show that a nanopore in a silicon membrane connected to a voltage source can be used as an electrically tunable ion filter. By applying a voltage between the heavily doped semiconductor and the electrolyte, it is possible to invert the ion population inside the nanopore and vary the conductance for both cations and anions in order to achieve selective conduction of ions even in the presence of significant surface charges in the membrane. Our model based on the solution of the Poisson equation and linear transport theory indicates that in narrow nanopores substantial gain can be achieved by controlling electrically the width of the charge double layer.

  9. Lithium ion batteries based on nanoporous silicon

    Science.gov (United States)

    Tolbert, Sarah H.; Nemanick, Eric J.; Kang, Chris Byung-Hwa

    2015-09-22

    A lithium ion battery that incorporates an anode formed from a Group IV semiconductor material such as porous silicon is disclosed. The battery includes a cathode, and an anode comprising porous silicon. In some embodiments, the anode is present in the form of a nanowire, a film, or a powder, the porous silicon having a pore diameters within the range between 2 nm and 100 nm and an average wall thickness of within the range between 1 nm and 100 nm. The lithium ion battery further includes, in some embodiments, a non-aqueous lithium containing electrolyte. Lithium ion batteries incorporating a porous silicon anode demonstrate have high, stable lithium alloying capacity over many cycles.

  10. Electrochemically etched nanoporous silicon membrane for separation of biological molecules in mixture

    Science.gov (United States)

    Burham, Norhafizah; Azlan Hamzah, Azrul; Yunas, Jumril; Yeop Majlis, Burhanuddin

    2017-07-01

    This paper presents a technique for separating biological molecules in mixture using nanoporous silicon membrane. Nanopores were formed using electrochemical etching process (ECE) by etching a prefabricated silicon membrane in hydrofluoric acid (HF) and ethanol, and then directly bonding it with PDMS to form a complete filtration system for separating biological molecules. Tygon S3™ tubings were used as fluid interconnection between PDMS molds and silicon membrane during testing. Electrochemical etching parameters were manipulated to control pore structure and size. In this work, nanopores with sizes of less than 50 nm, embedded on top of columnar structures have been fabricated using high current densities and variable HF concentrations. Zinc oxide was diluted with deionized (DI) water and mixed with biological molecules and non-biological particles, namely protein standard, serum albumin and sodium chloride. Zinc oxide particles were trapped on the nanoporous silicon surface, while biological molecules of sizes up to 12 nm penetrated the nanoporous silicon membrane. The filtered particles were inspected using a Zetasizer Nano SP for particle size measurement and count. The Zetasizer Nano SP results revealed that more than 95% of the biological molecules in the mixture were filtered out by the nanoporous silicon membrane. The nanoporous silicon membrane fabricated in this work is integratable into bio-MEMS and Lab-on-Chip components to separate two or more types of biomolecules at once. The membrane is especially useful for the development of artificial kidney.

  11. Nature of microscopic heat carriers in nanoporous silicon

    Science.gov (United States)

    Antidormi, Aleandro; Cartoixà, Xavier; Colombo, Luciano

    2018-05-01

    We performed a systematic analysis of the vibrational modes in nanoporous silicon for different values of porosity, separating them into extended modes (diffusons and propagons) and localized vibrations (locons). By calculating the density of states, the participation ratio, and the systems' dispersion curves, the spatial character of each mode as well as the effect of porosity on the thermal conductivity have been investigated. An increase of porosity is shown to promote the existence of increasingly localized modes on one side, and the progressive transformation of propagons to diffusons on the other. Finally, we provide evidence of the sizable contribution of locons to thermal transport found in large porosity samples and discuss the mechanism of energy transfer in terms of mode-mode autocorrelations and cross-correlations.

  12. Flexible, Penetrating Brain Probes Enabled by Advances in Polymer Microfabrication

    Directory of Open Access Journals (Sweden)

    Ahuva Weltman

    2016-10-01

    Full Text Available The acquisition of high-fidelity, long-term neural recordings in vivo is critically important to advance neuroscience and brain–machine interfaces. For decades, rigid materials such as metal microwires and micromachined silicon shanks were used as invasive electrophysiological interfaces to neurons, providing either single or multiple electrode recording sites. Extensive research has revealed that such rigid interfaces suffer from gradual recording quality degradation, in part stemming from tissue damage and the ensuing immune response arising from mechanical mismatch between the probe and brain. The development of “soft” neural probes constructed from polymer shanks has been enabled by advancements in microfabrication; this alternative has the potential to mitigate mismatch-related side effects and thus improve the quality of recordings. This review examines soft neural probe materials and their associated microfabrication techniques, the resulting soft neural probes, and their implementation including custom implantation and electrical packaging strategies. The use of soft materials necessitates careful consideration of surgical placement, often requiring the use of additional surgical shuttles or biodegradable coatings that impart temporary stiffness. Investigation of surgical implantation mechanics and histological evidence to support the use of soft probes will be presented. The review concludes with a critical discussion of the remaining technical challenges and future outlook.

  13. Nanopore arrays in a silicon membrane for parallel single-molecule detection: fabrication

    Science.gov (United States)

    Schmidt, Torsten; Zhang, Miao; Sychugov, Ilya; Roxhed, Niclas; Linnros, Jan

    2015-08-01

    Solid state nanopores enable translocation and detection of single bio-molecules such as DNA in buffer solutions. Here, sub-10 nm nanopore arrays in silicon membranes were fabricated by using electron-beam lithography to define etch pits and by using a subsequent electrochemical etching step. This approach effectively decouples positioning of the pores and the control of their size, where the pore size essentially results from the anodizing current and time in the etching cell. Nanopores with diameters as small as 7 nm, fully penetrating 300 nm thick membranes, were obtained. The presented fabrication scheme to form large arrays of nanopores is attractive for parallel bio-molecule sensing and DNA sequencing using optical techniques. In particular the signal-to-noise ratio is improved compared to other alternatives such as nitride membranes suffering from a high-luminescence background.

  14. Amphotericin B channels in phospholipid membrane-coated nanoporous silicon surfaces: implications for photovoltaic driving of ions across membranes.

    Science.gov (United States)

    Yilma, Solomon; Liu, Nangou; Samoylov, Alexander; Lo, Ting; Brinker, C Jeffrey; Vodyanoy, Vitaly

    2007-03-15

    The antimycotic agent amphotericin B (AmB) functions by forming complexes with sterols to form ion channels that cause membrane leakage. When AmB and cholesterol mixed at 2:1 ratio were incorporated into phospholipid bilayer membranes formed on the tip of patch pipettes, ion channel current fluctuations with characteristic open and closed states were observed. These channels were also functional in phospholipid membranes formed on nanoporous silicon surfaces. Electrophysiological studies of AmB-cholesterol mixtures that were incorporated into phospholipid membranes formed on the surface of nanoporous (6.5 nm pore diameter) silicon plates revealed large conductance ion channels ( approximately 300 pS) with distinct open and closed states. Currents through the AmB-cholesterol channels on nanoporous silicon surfaces can be driven by voltage applied via conventional electrical circuits or by photovoltaic electrical potential entirely generated when the nanoporous silicon surface is illuminated with a narrow laser beam. Electrical recordings made during laser illumination of AmB-cholesterol containing membrane-coated nanoporous silicon surfaces revealed very large conductance ion channels with distinct open and closed states. Our findings indicate that nanoporous silicon surfaces can serve as mediums for ion-channel-based biosensors. The photovoltaic properties of nanoporous silicon surfaces show great promise for making such biosensors addressable via optical technologies.

  15. Periodic arrays of deep nanopores made in silicon with reactive ion etching and deep UV lithography

    International Nuclear Information System (INIS)

    Woldering, Leon A; Tjerkstra, R Willem; Vos, Willem L; Jansen, Henri V; Setija, Irwan D

    2008-01-01

    We report on the fabrication of periodic arrays of deep nanopores with high aspect ratios in crystalline silicon. The radii and pitches of the pores were defined in a chromium mask by means of deep UV scan and step technology. The pores were etched with a reactive ion etching process with SF 6 , optimized for the formation of deep nanopores. We have realized structures with pitches between 440 and 750 nm, pore diameters between 310 and 515 nm, and depth to diameter aspect ratios up to 16. To the best of our knowledge, this is the highest aspect ratio ever reported for arrays of nanopores in silicon made with a reactive ion etching process. Our experimental results show that the etching rate of the nanopores is aspect-ratio-dependent, and is mostly influenced by the angular distribution of the etching ions. Furthermore we show both experimentally and theoretically that, for sub-micrometer structures, reducing the sidewall erosion is the best way to maximize the aspect ratio of the pores. Our structures have potential applications in chemical sensors, in the control of liquid wetting of surfaces, and as capacitors in high-frequency electronics. We demonstrate by means of optical reflectivity that our high-quality structures are very well suited as photonic crystals. Since the process studied is compatible with existing CMOS semiconductor fabrication, it allows for the incorporation of the etched arrays in silicon chips

  16. Effect of ultraviolet illumination and ambient gases on the photoluminescence and electrical properties of nanoporous silicon layer for organic vapor sensor.

    Science.gov (United States)

    Atiwongsangthong, Narin

    2012-08-01

    The purpose of this research, the nanoporous silicon layer were fabricated and investigated the physical properties such as photoluminescence and the electrical properties in order to develop organic vapor sensor by using nanoporous silicon. The Changes in the photoluminescence intensity of nanoporous silicon samples are studied during ultraviolet illumination in various ambient gases such as nitrogen, oxigen and vacuum. In this paper, the nanoporous silicon layer was used as organic vapor adsorption and sensing element. The advantage of this device are simple process compatible in silicon technology and usable in room temperature. The structure of this device consists of nanoporous silicon layer which is formed by anodization of silicon wafer in hydrofluoric acid solution and aluminum electrode which deposited on the top of nanoporous silicon layer by evaporator. The nanoporous silicon sensors were placed in a gas chamber with various organic vapor such as ethanol, methanol and isopropyl alcohol. From studying on electrical characteristics of this device, it is found that the nanoporous silicon layer can detect the different organic vapor. Therefore, the nanoporous silicon is important material for organic vapor sensor and it can develop to other applications about gas sensors in the future.

  17. Sensitivity of energy-packed compounds based on superfine and nanoporous silicon to pulsed electrical treatments

    Energy Technology Data Exchange (ETDEWEB)

    Zegrya, G. G. [Russian Academy of Sciences, Ioffe Physical–Technical Institute (Russian Federation); Savenkov, G. G. [Saint-Petersburg State Engineering Institute (Technical University) (Russian Federation); Morozov, V. A. [Saint-Petersburg State University (Russian Federation); Zegrya, A. G.; Ulin, N. V., E-mail: Ulin@mail.ioffe.ru; Ulin, V. P. [Russian Academy of Sciences, Ioffe Physical–Technical Institute (Russian Federation); Lukin, A. A. [Saint-Petersburg State Engineering Institute (Technical University) (Russian Federation); Bragin, V. A.; Oskin, I. A. [AO Scientific Production Association Poisk (Russian Federation); Mikhailov, Yu. M. [Russian Academy of Sciences, Institute of Problems of Chemical Physics (Russian Federation)

    2017-04-15

    The sensitivity of an energy-packed compound based on nanoporous silicon and calcium perchlorate to a high-current electron beam is studied. The initiation of explosive transformations in a mixture of potassium picrate with a highly dispersed powder of boron-doped silicon by means of a high-voltage discharge is examined. It is shown that explosive transformation modes (combustion and explosion) appear in the energy-packed compound under study upon its treatment with an electron beam. A relationship is established between the explosive transformation modes and the density of the energy-packed compound and between the breakdown (initiation) voltage and the mass fraction of the silicon powder.

  18. Automated and inexpensive method to manufacture solid- state nanopores and micropores in robust silicon wafers

    International Nuclear Information System (INIS)

    Vega, M; Lasorsa, C; Lerner, B; Perez, M; Granell, P

    2016-01-01

    In this work an easy, reproducible and inexpensive technique for the production of solid state nanopores and micropores using silicon wafer substrate is proposed. The technique is based on control of pore formation, by neutralization etchant (KOH) with a strong acid (HCl). Thus, a local neutralization is produced around the nanopore, which stops the silicon etching. The etching process was performed with 7M KOH at 80°C, where 1.23µm/min etching speed was obtained, similar to those published in literature. The control of the pore formation with the braking acid method was done using 12M HCl and different extreme conditions: i) at 25°C, ii) at 80°C and iii) at 80°C applying an electric potential. In these studies, it was found that nanopores and micropores can be obtained automatically and at a low cost. Additionally, the process was optimized to obtain clean silicon wafers after the pore fabrication process. This method opens the possibility for an efficient scale-up from laboratory production. (paper)

  19. Automated and inexpensive method to manufacture solid- state nanopores and micropores in robust silicon wafers

    Science.gov (United States)

    Vega, M.; Granell, P.; Lasorsa, C.; Lerner, B.; Perez, M.

    2016-02-01

    In this work an easy, reproducible and inexpensive technique for the production of solid state nanopores and micropores using silicon wafer substrate is proposed. The technique is based on control of pore formation, by neutralization etchant (KOH) with a strong acid (HCl). Thus, a local neutralization is produced around the nanopore, which stops the silicon etching. The etching process was performed with 7M KOH at 80°C, where 1.23µm/min etching speed was obtained, similar to those published in literature. The control of the pore formation with the braking acid method was done using 12M HCl and different extreme conditions: i) at 25°C, ii) at 80°C and iii) at 80°C applying an electric potential. In these studies, it was found that nanopores and micropores can be obtained automatically and at a low cost. Additionally, the process was optimized to obtain clean silicon wafers after the pore fabrication process. This method opens the possibility for an efficient scale-up from laboratory production.

  20. Initiation of explosive conversions in energy-saturated nanoporous silicon-based compounds with fast semiconductor switches and energy-releasing elements

    Science.gov (United States)

    Savenkov, G. G.; Kardo-Sysoev, A. F.; Zegrya, A. G.; Os'kin, I. A.; Bragin, V. A.; Zegrya, G. G.

    2017-10-01

    The first findings concerning the initiation of explosive conversions in energy-saturated nanoporous silicon-based compounds via the electrical explosion of a semiconductor bridge are presented. The obtained results indicate that the energy parameters of an explosive conversion depend on the mass of a combustible agent—namely, nanoporous silicon—and the silicon-doping type.

  1. Correlation of electrical conductivity and photoluminescence in nanoporous silicon

    International Nuclear Information System (INIS)

    Bouaicha, M.; Khardani, M.; Bessais, B.

    2006-01-01

    The effective electrical conductivity of p type porous silicon is determined both theoretically and experimentally for different porosities ranging from 30% to 80%. In this work, Effective Medium Approximation (EMA) model was used as a theoretical support. The porous silicon samples were prepared by the electrochemical etching method for different values of the anodic current. The porous material is assumed to be formed of three phases; vacuum, oxide and Si nanocrystallites. The analytical expression of the electrical conductivity of the Si nanocrystallites was established using the quantum confinement theory. This enables us to correlate the electrical conductivity of a PS layer, to the peak energy of its photoluminescence (PL) spectrum. A perfect agreement between the theoretical and the experimental electrical conductivity values was obtained for all prospected PS porosities. The results are discussed as regard to other works

  2. Modified MIS-structure based on nanoporous silicon with enhanced sensitivity to the hydrogen containing gases

    Energy Technology Data Exchange (ETDEWEB)

    Gorbanyuk, T.; Evtukh, A.; Litovchenko, V.; Solntsev, V. [Institute of Semiconductor Physics, Kiev (Ukraine)

    2008-07-01

    The gas sensitivity of metal-insulator-semiconductor (MIS)-structures based on nanoporous silicon with active electrodes from palladium/tungsten oxide composite has been studied. It was found that the using of palladium/tungsten oxide composite (instead of thin palladium film) leads to enhanced sensitivity of MIS structures to hydrogen sulphide in air. The mechanism of this phenomenon has been established. The enhanced H{sub 2}S sensitivity is explained in the following way. The microparticles of tungsten trioxide inside palladium matrix stimulate the dissociation of hydrogen sulphide molecules, and hydrogen atoms and/or protons flow down to palladium surface, are absorbed by palladium volume, diffuse to palladium/oxidized nanoporous silicon interface. Hydrogen atoms adsorbed at the interface are polarized and give rise to a dipole layer. As a result, the voltage shift of the capacity-voltage (C-V) curve proportional to the measured gas concentration is observed. The surface microstructure of Pd/WO{sub 3} composite was studied by AFM microscopy. The chemical content of the composite film has been investigated by SIMS. It was found that the composite film on nanoporous silicon surface poses the holes with the size about 0.05 {mu}m, the mean separation between tungsten oxide microparticles is 1-2 {mu}m. It also was found that the using of the additional double layer polymer film (polymer film (phthalocyanine zinc)/semicon-ductor film (cadmium sulphide)) on composite film surface leads to the additional enhancement of the gas sensitivity to hydrogen sulphide. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  3. The correlation of blue shift of photoluminescence and morphology of silicon nanoporous

    Energy Technology Data Exchange (ETDEWEB)

    Al-Jumaili, Batool E. B., E-mail: batooleneaze@gmail.com [Department of Physics, (UPM), Serdang, Selangor 43400 (Malaysia); Department of Physics, Anbar University (Iraq); Talib, Zainal A.; Josephine, L.Y.; Paiman, Suriati B.; Muh’d, Ibrahim B.; Mofdal, Manahil E. E. [Department of Physics, (UPM), Serdang, Selangor 43400 (Malaysia); Ahmed, Naser M.; Abdulateef, Sinan A. [School of Physics, USM, 11800 Penang (Malaysia); Al-Jumaily, Abdulmajeed H. J. [Department of Computer and Communication Systems Engineering, Universiti Putra Malaysia (UPM), Serdang, Selangor 43400 (Malaysia); Ramizy, Asmiet [Department of Physics, Anbar University (Iraq)

    2016-07-06

    Porous silicon with diameters ranging from 6.41 to 7.12 nm were synthesized via electrochemical etching by varied anodization current density in ethanoic solutions containing aqueous hydrofluoric acid up to 65 mA/cm{sup 2}.The luminescence properties of the nanoporous at room temperature were analyzed via photoluminescence spectroscopy. Photoluminescence PL spectra exhibit a broad emission band in the range of 360-700 nm photon energy. The PL spectrum has a blue shift in varied anodization current density; the blue shift incremented as the existing of anodization although the intensity decreased. The current blue shift is owning to alteration of silicon nanocrystal structure at the superficies. The superficial morphology of the PS layers consists of unified and orderly distribution of nanocrystalline Si structures, have high porosity around (93.75%) and high thickness 39.52 µm.

  4. Fabrication and optical characterization of light trapping silicon nanopore and nanoscrew devices

    International Nuclear Information System (INIS)

    Jin, Hyunjong; Logan Liu, G

    2012-01-01

    We have fabricated nanotextured Si substrates that exhibit controllable optical reflection intensities and colors. Si nanopore has a photon trapping nanostructure but has abrupt changes in the index of refraction displaying a darkened specular reflection. Nanoscrew Si shows graded refractive-index photon trapping structures that enable diffuse reflection to be as low as 2.2% over the visible wavelengths. By tuning the 3D nanoscale silicon structure, the optical reflection peak wavelength and intensity are changed in the wavelength range of 300–800 nm, making the surface have different reflectivity and apparent colors. The relation between the surface optical properties with the spatial features of the photon trapping nanostructures is examined. Integration of photon trapping structures with planar Si structure on the same substrate is also demonstrated. The tunable photon trapping silicon structures have potential applications in enhancing the performance of semiconductor photoelectric devices. (paper)

  5. Morphology dependent field emission characteristics of ZnS/silicon nanoporous pillar array

    Science.gov (United States)

    Wang, Ling Li; Zhao, Cheng Zhou; Kang, Li Ping; Liu, De Wei; Zhao, Hui Chun; Hao, Shan Peng; Zhang, Yuan Kai; Chen, Zhen Ping; Li, Xin Jian

    2016-10-01

    Through depositing zinc sulphide (ZnS) nanoparticals on silicon nanoporous pillar array (Si-NPA) and crater-shaped silicon nanoporous pillar array (c-Si-NPA) by chemical bath deposition (CBD) method, ZnS/Si-NPA and c-ZnS/Si-NPA were prepared and the field emission (FE) properties of them were investigated. The turn-on electric fields of were 3.8 V/mm for ZnS/Si-NPA and 5.0 V/mm for c-ZnS/Si-NPA, respectively. The lower turn-on electric fields of ZnS/Si-NPA than that of c-ZnS/Si-NPA were attributed to the different electric distribution of the field emitters causing by the different surface morphology of the two samples, which was further demonstrated via the simulated results by finite element modeling. The FN curves for the ZnS/Si-NPA showed two-slope behavior. All the results indicate that the morphology play an important role in the FE properties and designing an appropriate top morphology for the emitter is a very efficient way to improve the FE performance.

  6. Three dimensional analysis of nanoporous silicon particles for Li-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Roiban, Lucian, E-mail: lucian.roiban@insa-lyon.fr [Université de Lyon, Insa-Lyon, MATEIS, UMR5510 CNRS, 7 Avenue Jean Capelle, 69621, Villeurbanne cedex (France); Koneti, Siddardha [Université de Lyon, Insa-Lyon, MATEIS, UMR5510 CNRS, 7 Avenue Jean Capelle, 69621, Villeurbanne cedex (France); Wada, Takeshi, E-mail: wada-t@imr.tohoku.ac.jp [Institute for Materials Research, Tohoku University, Sendai, Miyagi 980-8577 (Japan); Kato, Hidemi [Institute for Materials Research, Tohoku University, Sendai, Miyagi 980-8577 (Japan); Cadete Santos Aires, Francisco J. [Université de Lyon, Université Lyon1, IRCELYON, UMR5256 CNRS, 2 Avenue Albert Einstein, 69626 Villeurbanne Cedex (France); Laboratory of Catalytic Research, National Research Tomsk State University, 36 Lenin Avenue, 634050 Tomsk (Russian Federation); Curelea, Sergiu; Epicier, Thierry; Maire, Eric [Université de Lyon, Insa-Lyon, MATEIS, UMR5510 CNRS, 7 Avenue Jean Capelle, 69621, Villeurbanne cedex (France)

    2017-02-15

    Bulk nanoporous silicon prepared by top-down method form Li-ion batteries was investigated combining different conventional technique such as nitrogen physisorption and high resolution electron microscopy with electron tomography. It was found that the Si nanorods are forming porous aggregates with a half of the volume of the particle occupied by pores. The nanorods are preferentially oriented along the main axis of the aggregate. The porosity and the lack of compaction between the aggregates provide space for the Si expansion during the lithiation process. It was found that the Si nanorods mainly expose the (111) family plane as an external faces. The size distributions of the porous and solid phases in a granule were found to be similar. The pores represent 50% of the total volume of an aggregate. The shape orientation of the particles was quantified and it was found to exhibit a narrow distribution. - Highlights: •Bulk nanoporous silicon for Li-ion batteries is studied by HRTEM and electron tomography. •The crystalline facets of Si nanorods are formed by (111) plains. •The lack of compactness between Si nanorods provides 50% of porous volume. •The Si nanorods are oriented along a preferential axis.

  7. Silicon-on-insulator based nanopore cavity arrays for lipid membrane investigation.

    Science.gov (United States)

    Buchholz, K; Tinazli, A; Kleefen, A; Dorfner, D; Pedone, D; Rant, U; Tampé, R; Abstreiter, G; Tornow, M

    2008-11-05

    We present the fabrication and characterization of nanopore microcavities for the investigation of transport processes in suspended lipid membranes. The cavities are situated below the surface of silicon-on-insulator (SOI) substrates. Single cavities and large area arrays were prepared using high resolution electron-beam lithography in combination with reactive ion etching (RIE) and wet chemical sacrificial underetching. The locally separated compartments have a circular shape and allow the enclosure of picoliter volume aqueous solutions. They are sealed at their top by a 250 nm thin Si membrane featuring pores with diameters from 2 µm down to 220 nm. The Si surface exhibits excellent smoothness and homogeneity as verified by AFM analysis. As biophysical test system we deposited lipid membranes by vesicle fusion, and demonstrated their fluid-like properties by fluorescence recovery after photobleaching. As clearly indicated by AFM measurements in aqueous buffer solution, intact lipid membranes successfully spanned the pores. The nanopore cavity arrays have potential applications in diagnostics and pharmaceutical research on transmembrane proteins.

  8. Fabrication and Optimization of a Nanoporous Platinum Electrode and a Non-enzymatic Glucose Micro-sensor on Silicon

    Directory of Open Access Journals (Sweden)

    Younghun Kim

    2008-10-01

    Full Text Available In this paper, optimal conditions for fabrication of nanoporous platinum (Pt were investigated in order to use it as a sensitive sensing electrode for silicon CMOS integrable non-enzymatic glucose micro-sensor applications. Applied charges, voltages, and temperatures were varied during the electroplating of Pt into the formed nonionic surfactant C16EO8 nano-scaled molds in order to fabricate nanoporous Pt electrodes with large surface roughness factor (RF, uniformity, and reproducibility. The fabricated nanoporous Pt electrodes were characterized using atomic force microscopy (AFM and electrochemical cyclic voltammograms. Optimal electroplating conditions were determined to be an applied charge of 35 mC/mm2, a voltage of -0.12 V, and a temperature of 25 °C, respectively. The optimized nanoporous Pt electrode had an electrochemical RF of 375 and excellent reproducibility. The optimized nanoporous Pt electrode was applied to fabricate non-enzymatic glucose micro-sensor with three electrode systems. The fabricated sensor had a size of 3 mm x 3 mm, air gap of 10 µm, working electrode (WE area of 4.4 mm2, and sensitivity of 37.5 µA•L/mmol•cm2. In addition, it showed large detection range from 0.05 to 30 mmolL-1 and stable recovery responsive to the step changes in glucose concentration.

  9. Responsivity Dependent Anodization Current Density of Nanoporous Silicon Based MSM Photodetector

    Directory of Open Access Journals (Sweden)

    Batool Eneaze B. Al-Jumaili

    2016-01-01

    Full Text Available Achieving a cheap and ultrafast metal-semiconductor-metal (MSM photodetector (PD for very high-speed communications is ever-demanding. We report the influence of anodization current density variation on the response of nanoporous silicon (NPSi based MSM PD with platinum (Pt contact electrodes. Such NPSi samples are grown from n-type Si (100 wafer using photoelectrochemical etching with three different anodization current densities. FESEM images of as-prepared samples revealed the existence of discrete pores with spherical and square-like shapes. XRD pattern displayed the growth of nanocrystals with (311 lattice orientation. The nanocrystallite sizes obtained using Scherrer formula are found to be between 20.8 nm and 28.6 nm. The observed rectifying behavior in the I-V characteristics is ascribed to the Pt/PSi/n-Si Schottky barrier formation, where the barrier height at the Pt/PSi interface is estimated to be 0.69 eV. Furthermore, this Pt/PSi/Pt MSM PD achieved maximum responsivity of 0.17 A/W and quantum efficiency as much as 39.3%. The photoresponse of this NPSi based MSM PD demonstrated excellent repeatability, fast response, and enhanced saturation current with increasing anodization current density.

  10. Silicon nanopore membrane (SNM) for islet encapsulation and immunoisolation under convective transport

    Science.gov (United States)

    Song, Shang; Faleo, Gaetano; Yeung, Raymond; Kant, Rishi; Posselt, Andrew M.; Desai, Tejal A.; Tang, Qizhi; Roy, Shuvo

    2016-03-01

    Problems associated with islet transplantation for Type 1 Diabetes (T1D) such as shortage of donor cells, use of immunosuppressive drugs remain as major challenges. Immune isolation using encapsulation may circumvent the use of immunosuppressants and prolong the longevity of transplanted islets. The encapsulating membrane must block the passage of host’s immune components while providing sufficient exchange of glucose, insulin and other small molecules. We report the development and characterization of a new generation of semipermeable ultrafiltration membrane, the silicon nanopore membrane (SNM), designed with approximately 7 nm-wide slit-pores to provide middle molecule selectivity by limiting passage of pro-inflammatory cytokines. Moreover, the use of convective transport with a pressure differential across the SNM overcomes the mass transfer limitations associated with diffusion through nanometer-scale pores. The SNM exhibited a hydraulic permeability of 130 ml/hr/m2/mmHg, which is more than 3 fold greater than existing polymer membranes. Analysis of sieving coefficients revealed 80% reduction in cytokines passage through SNM under convective transport. SNM protected encapsulated islets from infiltrating cytokines and retained islet viability over 6 hours and remained responsive to changes in glucose levels unlike non-encapsulated controls. Together, these data demonstrate the novel membrane exhibiting unprecedented hydraulic permeability and immune-protection for islet transplantation therapy.

  11. Quantitative differentiation of multiple virus in blood using nanoporous silicon oxide immunosensor and artificial neural network.

    Science.gov (United States)

    Chakraborty, W; Ray, R; Samanta, N; RoyChaudhuri, C

    2017-12-15

    In spite of the rapid developments in various nanosensor technologies, it still remains challenging to realize a reliable ultrasensitive electrical biosensing platform which will be able to detect multiple viruses in blood simultaneously with a fairly high reproducibility without using secondary labels. In this paper, we have reported quantitative differentiation of Hep-B and Hep-C viruses in blood using nanoporous silicon oxide immunosensor array and artificial neural network (ANN). The peak frequency output (f p ) from the steady state sensitivity characteristics and the first cut off frequency (f c ) from the transient characteristics have been considered as inputs to the multilayer ANN. Implementation of several classifier blocks in the ANN architecture and coupling them with both the sensor chips, functionalized with Hep-B and Hep-C antibodies have enabled the quantification of the viruses with an accuracy of around 95% in the range of 0.04fM-1pM and with an accuracy of around 90% beyond 1pM and within 25nM in blood serum. This is the most sensitive report on multiple virus quantification using label free method. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Removal of endotoxin from deionized water using micromachined silicon nanopore membranes

    International Nuclear Information System (INIS)

    Smith, Ross A; Fissell, William H; Fleischman, Aaron J; Roy, Shuvo; Goldman, Ken; Zorman, Christian A

    2011-01-01

    Endotoxins are lipopolysaccharide components of the cell membrane of Gram-negative bacteria that trigger the body's innate immune system and can cause shock and death. Water for medical therapy, including parenteral and dialysate solutions, must be free of endotoxin. This purity is challenging to achieve as many Gram-negative bacteria are endemic in the environment, and can thrive in harsh, nutrient-poor conditions. Current methods for removing endotoxin include distillation and reverse osmosis, both of which are resource intensive processes. Membranes that present an absolute barrier to macromolecular passage may be capable of delivering pure water for biomedical applications. In this work, endotoxin has been filtered from aqueous solutions using silicon nanopore membranes (SNMs) with monodisperse pore size distributions. SNMs with critical pore sizes between 26 and 49 nm were challenged with solutions of deionized water spiked with endotoxin and with Pseudomonas cepacia. The filtrate produced by the SNM from Pseudomonas-contaminated water had <1.0 endotoxin unit (EU) ml −1 , which meets standards for dialysate purity. This approach suggests a technique for single-step cleanup of heavily contaminated water that may be suitable for field or clinical use

  13. Fabrication of nanopores in multi-layered silicon-based membranes using focused electron beam induced etching with XeF_2 gas

    International Nuclear Information System (INIS)

    Liebes-Peer, Yael; Bandalo, Vedran; Sökmen, Ünsal; Tornow, Marc; Ashkenasy, Nurit

    2016-01-01

    The emergent technology of using nanopores for stochastic sensing of biomolecules introduces a demand for the development of simple fabrication methodologies of nanopores in solid state membranes. This process becomes particularly challenging when membranes of composite layer architecture are involved. To overcome this challenge we have employed a focused electron beam induced chemical etching process. We present here the fabrication of nanopores in silicon-on-insulator based membranes in a single step process. In this process, chemical etching of the membrane materials by XeF_2 gas is locally accelerated by an electron beam, resulting in local etching, with a top membrane oxide layer preventing delocalized etching of the silicon underneath. Nanopores with a funnel or conical, 3-dimensional (3D) shape can be fabricated, depending on the duration of exposure to XeF_2, and their diameter is dominated by the time of exposure to the electron beam. The demonstrated ability to form high-aspect ratio nanopores in comparably thick, multi-layered silicon based membranes allows for an easy integration into current silicon process technology and hence is attractive for implementation in biosensing lab-on-chip fabrication technologies. (author)

  14. DNA Physical Mapping via the Controlled Translocation of Single Molecules through a 5-10nm Silicon Nitride Nanopore

    Science.gov (United States)

    Stein, Derek; Reisner, Walter; Jiang, Zhijun; Hagerty, Nick; Wood, Charles; Chan, Jason

    2009-03-01

    The ability to map the binding position of sequence-specific markers, including transcription-factors, protein-nucleic acids (PNAs) or deactivated restriction enzymes, along a single DNA molecule in a nanofluidic device would be of key importance for the life-sciences. Such markers could give an indication of the active genes at particular stage in a cell's transcriptional cycle, pinpoint the location of mutations or even provide a DNA barcode that could aid in genomics applications. We have developed a setup consisting of a 5-10 nm nanopore in a 20nm thick silicon nitride film coupled to an optical tweezer setup. The translocation of DNA across the nanopore can be detected via blockades in the electrical current through the pore. By anchoring one end of the translocating DNA to an optically trapped microsphere, we hope to stretch out the molecule in the nanopore and control the translocation speed, enabling us to slowly scan across the genome and detect changes in the baseline current due to the presence of bound markers.

  15. Brittle-to-ductile transition of lithiated silicon electrodes: Crazing to stable nanopore growth

    International Nuclear Information System (INIS)

    Wang, Haoran; Chew, Huck Beng; Wang, Xueju; Xia, Shuman

    2015-01-01

    Using first principle calculations, we uncover the underlying mechanisms explaining the brittle-to-ductile transition of Li x Si electrodes in lithium ion batteries with increasing Li content. We show that plasticity initiates at x = ∼ 0.5 with the formation of a craze-like network of nanopores separated by Si–Si bonds, while subsequent failure is still brittle-like with the breaking of Si–Si bonds. Transition to ductile behavior occurs at x ⩾ 1 due to the increased density of highly stretchable Li–Li bonds, which delays nanopore formation and stabilizes nanopore growth. Collapse of the nanopores during unloading of the Li x Si alloys leads to significant strain recovery

  16. Brittle-to-ductile transition of lithiated silicon electrodes: Crazing to stable nanopore growth

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Haoran; Chew, Huck Beng, E-mail: hbchew@illinois.edu [Department of Aerospace Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States); Wang, Xueju; Xia, Shuman [Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States)

    2015-09-14

    Using first principle calculations, we uncover the underlying mechanisms explaining the brittle-to-ductile transition of Li{sub x}Si electrodes in lithium ion batteries with increasing Li content. We show that plasticity initiates at x = ∼ 0.5 with the formation of a craze-like network of nanopores separated by Si–Si bonds, while subsequent failure is still brittle-like with the breaking of Si–Si bonds. Transition to ductile behavior occurs at x ⩾ 1 due to the increased density of highly stretchable Li–Li bonds, which delays nanopore formation and stabilizes nanopore growth. Collapse of the nanopores during unloading of the Li{sub x}Si alloys leads to significant strain recovery.

  17. Brittle-to-ductile transition of lithiated silicon electrodes: Crazing to stable nanopore growth.

    Science.gov (United States)

    Wang, Haoran; Wang, Xueju; Xia, Shuman; Chew, Huck Beng

    2015-09-14

    Using first principle calculations, we uncover the underlying mechanisms explaining the brittle-to-ductile transition of LixSi electrodes in lithium ion batteries with increasing Li content. We show that plasticity initiates at x = ∼ 0.5 with the formation of a craze-like network of nanopores separated by Si-Si bonds, while subsequent failure is still brittle-like with the breaking of Si-Si bonds. Transition to ductile behavior occurs at x ⩾ 1 due to the increased density of highly stretchable Li-Li bonds, which delays nanopore formation and stabilizes nanopore growth. Collapse of the nanopores during unloading of the LixSi alloys leads to significant strain recovery.

  18. SERS activity of Au nanoparticles coated on an array of carbon nanotube nested into silicon nanoporous pillar

    International Nuclear Information System (INIS)

    Jiang Weifen; Zhang Yanfeng; Wang Yusheng; Xu Lei; Li Xinjian

    2011-01-01

    A novel composite structure, Au nanoparticles coated on a nest-shaped array of carbon nanotube nested into a silicon nanoporous pillar array (Au/NACNT/Si-NPA), was fabricated for surface-enhanced Raman scattering (SERS). The morphology of the Au/NACNT/Si-NPA composite structure was characterized with the aid of scanning electron microscopy, X-ray diffraction instrumentation and Transmission electron microscopy. Compared with SERS of rhodamine 6G (R6G) adsorbed on SERS-active Au substrate reported, the SERS signals of R6G adsorbed on these gold nanoparticles were obviously improved. This was attributed to the enlarged specific surface area for adsorption of target molecules brought by the nest-shaped CNTs structure.

  19. Raman light scattering in nanoporous carbon obtained from carbides of silicon and titanium

    International Nuclear Information System (INIS)

    Danishevskij, A.M.; Smorgonskaya, Eh.A.; Gordeev, S.K.; Grechinskaya, A.V.

    2001-01-01

    The Raman spectra in nanoporous carbon obtained through the chemical reaction from the polycrystal α-SiC and TiC are studied. It is shown that the spectra have a multicomponent character differentiating the considered group of materials from graphites and disordered carbon structures. The series of low-frequency modes is registered. The anisotropy and dispersion effects are identified. The results testify to the cluster structure of nanoporous carbon and dimensional quantization of electron and vibrational spectra in the carbon nanoclusters. The fine fragments of curved or fractures graphed sheets are the basic structural elements of nanoclusters in the porous skeleton. The presence of fragments close by structure to the tense cubic or hexagonal diamond is also notes [ru

  20. Near-Infrared Imaging Method for the In Vivo Assessment of the Biodistribution of Nanoporous Silicon Particles

    Directory of Open Access Journals (Sweden)

    Ennio Tasciotti

    2011-01-01

    Full Text Available In the development of new nanoparticle-based technologies for therapeutic and diagnostic purposes, understanding the fate of nanoparticles in the body is crucial. We recently developed a multistage vector delivery system comprising biodegradable and biocompatible nanoporous silicon particles (first-stage microparticles [S1MPs] able to host, protect, and deliver second-stage therapeutic and diagnostic nanoparticles (S2NPs on intravenous injection. This delivery system aims at sequentially overcoming the biologic barriers en route to the target delivery site by separating and assigning tasks to the coordinated logic-embedded vectors constituting it. In this work, by conjugating a near-infrared dye on the surface of the S1MP without compromising the porous structure and potential loading of S2NPs, we were able to monitor the in vivo distribution of S1MPs in healthy mice using an optical imaging system. It was observed that particles predominantly accumulated in the liver and spleen at the end of 24 hours. Further quantification of S1MPs in the major organs of the animals by elemental analysis of silicon using inductively coupled plasma-atomic electron spectroscopy verified the accuracy of in vivo near-infrared imaging as a tool for evaluation of nanovector biodistribution.

  1. TRANSFORMATIONS IN NANO-DIAMONDS WITH FORMATION OF NANO-POROUS SILICON CARBIDE AT HIGH PRESSURE

    Directory of Open Access Journals (Sweden)

    V. N. Kovalevsky

    2010-01-01

    Full Text Available The paper contains investigations on regularities of diamond - silicon carbide composite structure formation at impact-wave excitation. It has been determined that while squeezing a porous blank containing Si (SiC nano-diamond by explosive detonation products some processes are taking place such as diamond nano-particles consolidation, reverse diamond transition into graphite, fragments formation from silicon carbide. A method for obtaining high-porous composites with the presence of ultra-disperse diamond particles has been developed. Material with three-dimensional high-porous silicon-carbide structure has been received due to nano-diamond graphitation at impact wave transmission and plastic deformation. The paper reveals nano-diamonds inverse transformation into graphite and its subsequent interaction with the silicon accompanied by formation of silicon-carbide fragments with dimensions of up to 100 nm.

  2. Characterization of electronic structures from CdS/Si nanoheterostructure array based on silicon nanoporous pillar array

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yong, E-mail: liyong@pdsu.edu.cn [Department of Physics and Solar Energy Research Center, Pingdingshan University, Pingdingshan 467000 (China); Song, Xiao Yan [Department of Mathematics and Information Science, North China University of Water Resources and Electric Power, Zhengzhou 450045 (China); Song, Yue Li; Ji, Peng Fei; Zhou, Feng Qun; Tian, Ming Li; Huang, Hong Chun [Department of Physics and Solar Energy Research Center, Pingdingshan University, Pingdingshan 467000 (China); Li, Xin Jian [Department of Physics and Laboratory of Material Physics, Zhengzhou University, Zhengzhou 450052 (China)

    2016-02-15

    Highlights: • CdS/Si nanoheterostructure array has been fabricated through a CBD method. • The electronic properties have been investigated by the I–V and C–V techniques. • The onset voltages, characteristic frequency and built-in potential are investigated. • The electronic structures can be tuned through the annealing treatments. - Abstract: The electronic properties of heterostructures are very important to its applications in the field of optoelectronic devices. Understanding and control of electronic properties are very necessary. CdS/Si nanoheterostructure array have been fabricated through growing CdS nanocrystals on the silicon nanoporous pillar array using a chemical bath deposition method. The electronic properties of CdS nanoheterostructure array have been investigated by the current–voltage, complex impedance spectroscopy and capacitance–voltage techniques. The onset voltages, characteristic frequency and built-in potential are gradually increased with increasing the annealing temperature. It is indicated that the electronic structures of CdS/Si nanoheterostructure array can be tuned through the annealing treatments.

  3. Characterization of electronic structures from CdS/Si nanoheterostructure array based on silicon nanoporous pillar array

    International Nuclear Information System (INIS)

    Li, Yong; Song, Xiao Yan; Song, Yue Li; Ji, Peng Fei; Zhou, Feng Qun; Tian, Ming Li; Huang, Hong Chun; Li, Xin Jian

    2016-01-01

    Highlights: • CdS/Si nanoheterostructure array has been fabricated through a CBD method. • The electronic properties have been investigated by the I–V and C–V techniques. • The onset voltages, characteristic frequency and built-in potential are investigated. • The electronic structures can be tuned through the annealing treatments. - Abstract: The electronic properties of heterostructures are very important to its applications in the field of optoelectronic devices. Understanding and control of electronic properties are very necessary. CdS/Si nanoheterostructure array have been fabricated through growing CdS nanocrystals on the silicon nanoporous pillar array using a chemical bath deposition method. The electronic properties of CdS nanoheterostructure array have been investigated by the current–voltage, complex impedance spectroscopy and capacitance–voltage techniques. The onset voltages, characteristic frequency and built-in potential are gradually increased with increasing the annealing temperature. It is indicated that the electronic structures of CdS/Si nanoheterostructure array can be tuned through the annealing treatments.

  4. Effect of Etching Parameter on Pore Size and Porosity of Electrochemically Formed Nanoporous Silicon

    Directory of Open Access Journals (Sweden)

    Pushpendra Kumar

    2007-01-01

    Full Text Available The most common fabrication technique of porous silicon (PS is electrochemical etching of a crystalline silicon wafer in a hydrofluoric (HF acid-based solution. The electrochemical process allows for precise control of the properties of PS such as thickness of the porous layer, porosity, and average pore diameter. The control of these properties of PS was shown to depend on the HF concentration in the used electrolyte, the applied current density, and the thickness of PS. The change in pore diameter, porosity, and specific surface area of PS was investigated by measuring nitrogen sorption isotherms.

  5. A tunable sub-100 nm silicon nanopore array with an AAO membrane mask: reducing unwanted surface etching by introducing a PMMA interlayer

    Science.gov (United States)

    Lim, Namsoo; Pak, Yusin; Kim, Jin Tae; Hwang, Youngkyu; Lee, Ryeri; Kumaresan, Yogeenth; Myoung, Nosoung; Ko, Heung Cho; Jung, Gun Young

    2015-08-01

    Highly ordered silicon (Si) nanopores with a tunable sub-100 nm diameter were fabricated by a CF4 plasma etching process using an anodic aluminum oxide (AAO) membrane as an etching mask. To enhance the conformal contact of the AAO membrane mask to the underlying Si substrate, poly(methyl methacrylate) (PMMA) was spin-coated on top of the Si substrate prior to the transfer of the AAO membrane. The AAO membrane mask was fabricated by two-step anodization and subsequent removal of the aluminum support and the barrier layer, which was then transferred to the PMMA-coated Si substrate. Contact printing was performed on the sample with a pressure of 50 psi and a temperature of 120 °C to make a conformal contact of the AAO membrane mask to the Si substrate. The CF4 plasma etching was conducted to transfer nanopores onto the Si substrate through the PMMA interlayer. The introduced PMMA interlayer prevented unwanted surface etching of the Si substrate by eliminating the etching ions and radicals bouncing at the gap between the mask and the substrate, resulting in a smooth Si nanopore array.Highly ordered silicon (Si) nanopores with a tunable sub-100 nm diameter were fabricated by a CF4 plasma etching process using an anodic aluminum oxide (AAO) membrane as an etching mask. To enhance the conformal contact of the AAO membrane mask to the underlying Si substrate, poly(methyl methacrylate) (PMMA) was spin-coated on top of the Si substrate prior to the transfer of the AAO membrane. The AAO membrane mask was fabricated by two-step anodization and subsequent removal of the aluminum support and the barrier layer, which was then transferred to the PMMA-coated Si substrate. Contact printing was performed on the sample with a pressure of 50 psi and a temperature of 120 °C to make a conformal contact of the AAO membrane mask to the Si substrate. The CF4 plasma etching was conducted to transfer nanopores onto the Si substrate through the PMMA interlayer. The introduced PMMA interlayer

  6. Enhanced optical output power of InGaN/GaN light-emitting diodes grown on a silicon (111) substrate with a nanoporous GaN layer.

    Science.gov (United States)

    Lee, Kwang Jae; Chun, Jaeyi; Kim, Sang-Jo; Oh, Semi; Ha, Chang-Soo; Park, Jung-Won; Lee, Seung-Jae; Song, Jae-Chul; Baek, Jong Hyeob; Park, Seong-Ju

    2016-03-07

    We report the growth of InGaN/GaN multiple quantum wells blue light-emitting diodes (LEDs) on a silicon (111) substrate with an embedded nanoporous (NP) GaN layer. The NP GaN layer is fabricated by electrochemical etching of n-type GaN on the silicon substrate. The crystalline quality of crack-free GaN grown on the NP GaN layer is remarkably improved and the residual tensile stress is also decreased. The optical output power is increased by 120% at an injection current of 20 mA compared with that of conventional LEDs without a NP GaN layer. The large enhancement of optical output power is attributed to the reduction of threading dislocation, effective scattering of light in the LED, and the suppression of light propagation into the silicon substrate by the NP GaN layer.

  7. Carbon Nanofiber/3D Nanoporous Silicon Hybrids as High Capacity Lithium Storage Materials.

    Science.gov (United States)

    Park, Hyeong-Il; Sohn, Myungbeom; Kim, Dae Sik; Park, Cheolho; Choi, Jeong-Hee; Kim, Hansu

    2016-04-21

    Carbon nanofiber (CNF)/3D nanoporous (3DNP) Si hybrid materials were prepared by chemical etching of melt-spun Si/Al-Cu-Fe alloy nanocomposites, followed by carbonization using a pitch. CNFs were successfully grown on the surface of 3DNP Si particles using residual Fe impurities after acidic etching, which acted as a catalyst for the growth of CNFs. The resulting CNF/3DNP Si hybrid materials showed an enhanced cycle performance up to 100 cycles compared to that of the pristine Si/Al-Cu-Fe alloy nanocomposite as well as that of bare 3DNP Si particles. These results indicate that CNFs and the carbon coating layer have a beneficial effect on the capacity retention characteristics of 3DNP Si particles by providing continuous electron-conduction pathways in the electrode during cycling. The approach presented here provides another way to improve the electrochemical performances of porous Si-based high capacity anode materials for lithium-ion batteries. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Spectroscopy of nanosized composites silicon-organic polymer/nanoporous silicas

    International Nuclear Information System (INIS)

    Ostapenko, N.; Kozlova, N.; Suto, S.; Watanabe, A.

    2006-01-01

    Fluorescence and excitation spectra (T=5-290 K) of nanosized silicon-organic polymers poly(di-n-hexylsilane) and poly(methyl(phenyl)silane) incorporated into porous silica materials MCM-41 and SBA-15 have been studied with varying pore diameter from 2.8 to 10 nm. The controlled variation of the pore diameter in a wide range (2.8-10 nm) permitted us, for the first time, to investigate the optical properties of the polymers on their transition from isolated macromolecules to a film. It is found that this transition depends on polymer type and occurs via the formation of new spatially independent structures of the polymers not observed in the spectra of the film, namely, via the formation of disordered and (or) ordered conformations of polymer chains and clusters

  9. A Three-Dimensional Nanoporous Silicon Anode for High-Energy Density Lithium-ion Batteries, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR phase I program is directed toward the development of novel, nanoporous silica anodes for low-earth-orbiting (LEO) spacecraft power applications. Silica...

  10. Multi-Composite Bioactive Osteogenic Sponges Featuring Mesenchymal Stem Cells, Platelet-Rich Plasma, Nanoporous Silicon Enclosures, and Peptide Amphiphiles for Rapid Bone Regeneration

    Directory of Open Access Journals (Sweden)

    Dongmei Fan

    2011-06-01

    Full Text Available A novel bioactive sponge was created with a composite of type I collagen sponges or porous poly(e-caprolactone (PCL scaffolds, platelet-rich plasma (PRP, BMP2-loaded nanoporous silicon enclosure (NSE microparticles, mineralizing peptide amphiphiles (PA, and mesenchymal stem cells (MSC. Primary MSC from cortical bone (CB  tissue proved to form more and larger colony units, as well as produce more mineral matrix under osteogenic differentiation, than MSC from bone marrow (BM. Coating pre-treatments were optimized for maximum cell adhesion and mineralization, while a PRP-based gel carrier was created to efficiently deliver and retain MSC and  microparticles within a porous scaffold while simultaneously promoting cell recruitment, proliferation, and angiogenesis. Components and composite sponges were evaluated for osteogenic differentiation in vitro. Osteogenic sponges were loaded with MSC, PRP, PA, and NSE and implanted subcutaneously in rats to evaluate the formation of bone tissue and angiogenesis in vivo. It was found that the combination of a collagen sponge with CB MSC, PRP, PA, and the BMP2-releasing NSE formed the most bone and was most vascularized by four weeks compared to analogous composites featuring BM MSC or PCL or lacking PRP, PA, and NSE. This study indicates that CB MSC should be considered as an alternative to marrow as a source of stem cells, while the PRP-PA cell and microparticle delivery system may be utilized for diverse tissue engineering applications.

  11. Investigation of the quenched surfaces of visibly luminescent macro/nanoporous silicon under the exposure of typical neuron culture media

    International Nuclear Information System (INIS)

    Unal, B.

    2015-01-01

    In this research paper, the quenching effects of visible photoluminescence of porous silicon relevant to doping types under an exposure of culture media such as Dulbecco's Modified Eagle's Medium and Phosphate-Buffered Saline have been studied extensively in order to realize the application of a cell culture growth technique for porous silicon, in which biocompatibility is directly based on its size-dependent structures and morphologies. This could restrain the combination of either macro or micro-/nano-dimensional silicon morphologies by stain-etching single crystalline Si surfaces. The dopant-related quenching effect of well-known neuron culture media over visible photoluminescent porous silicon surface is found to be quite obvious for the two culture media mentioned above. Scanning electron microscope images of the cultured neuron cells over porous Si show how they have been linked to, and communicated with, each other, and directed along porous channels, fabricated by a photo lithographic technique. (authors)

  12. Controlling the role of nanopore morphology in capillary condensation.

    Science.gov (United States)

    Casanova, Fèlix; Chiang, Casey E; Ruminski, Anne M; Sailor, Michael J; Schuller, Ivan K

    2012-05-01

    The effect of pore morphology on capillary condensation and evaporation in nanoporous silicon is studied experimentally. A variety of cooperative and local effects are observed in tailored nanopores with well-defined regions by directly probing gas adsorption in each region using optical interferometry. All observations are ascribed to the ability of the nanopore region to access the gas reservoir directly and the nucleation of liquid bridges at local heterogeneities within the nanopore region. These assumptions, consistent with recent simulations, can be extended to any real nanoporous system.

  13. Cascaded nano-porous silicon for high sensitive biosensing and functional group distinguishing by Mid-IR spectra.

    Science.gov (United States)

    Nguyen, Minh-Hang; Tsai, Hau-Jie; Wu, Jen-Kuei; Wu, Yi-Shiuan; Lee, Ming-Chang; Tseng, Fan-Gang

    2013-09-15

    We present a chemical-biosensor in the Mid-IR range and based on cascaded porous silicon made on p- and n-type (100) silicon substrates of resistivities between 0.001Ωcm and 0.005Ωcm. The stacked porous layers of various porosities (20-80%) and thicknesses (5-9μm) are formed by successive electrochemical etchings with different current densities. Working with FTIR technique that possesses fast response, high sensitivity, and capability of detecting and identifying functional groups, the cascaded porous structures provided enhanced refractive index sensitivities and reduced detection limits in chemical and biodetection. The largest wavenumber shifts were 50cm(-1)/mM obtained for d-(+)-glucose and 96cm(-1)/μg/mL for Cy5-conjungated Rabbit Anti-Mouse IgG. The lowest detectable concentration of glucose was 80μM (1.4mg/mL) with PS porosity of 40% and thickness of about 9μm while it was 40ng/mL for Cy5-conjugated Rabbit Anti-Mouse IgG which is 2.5×10(5) folds better than those in literature. Copyright © 2013 Elsevier B.V. All rights reserved.

  14. Thermal conductivity model for nanoporous thin films

    Science.gov (United States)

    Huang, Congliang; Zhao, Xinpeng; Regner, Keith; Yang, Ronggui

    2018-03-01

    Nanoporous thin films have attracted great interest because of their extremely low thermal conductivity and potential applications in thin thermal insulators and thermoelectrics. Although there are some numerical and experimental studies about the thermal conductivity of nanoporous thin films, a simplified model is still needed to provide a straightforward prediction. In this paper, by including the phonon scattering lifetimes due to film thickness boundary scattering, nanopore scattering and the frequency-dependent intrinsic phonon-phonon scattering, a fitting-parameter-free model based on the kinetic theory of phonon transport is developed to predict both the in-plane and the cross-plane thermal conductivities of nanoporous thin films. With input parameters such as the lattice constants, thermal conductivity, and the group velocity of acoustic phonons of bulk silicon, our model shows a good agreement with available experimental and numerical results of nanoporous silicon thin films. It illustrates that the size effect of film thickness boundary scattering not only depends on the film thickness but also on the size of nanopores, and a larger nanopore leads to a stronger size effect of the film thickness. Our model also reveals that there are different optimal structures for getting the lowest in-plane and cross-plane thermal conductivities.

  15. Direct detection of illicit drugs from biological fluids by desorption/ionization mass spectrometry with nanoporous silicon microparticles.

    Science.gov (United States)

    Guinan, T M; Kirkbride, P; Della Vedova, C B; Kershaw, S G; Kobus, H; Voelcker, N H

    2015-12-07

    Surface-assisted laser desorption/ionization mass spectrometry (SALDI-MS) is a high throughput analytical technique capable of detecting low molecular weight analytes, including illicit drugs, and with potential applications in forensic toxicology as well as athlete and workplace testing, particularly for biological fluids (oral fluids, urine and blood). However, successful detection of illicit drugs using SALDI-MS often requires extraction steps to reduce the inherent complexity of biological fluids. Here, we demonstrate an all-in-one extraction and analytical system consisting of hydrophobically functionalized porous silicon microparticles (pSi-MPs) for affinity SALDI-MS of prescription and illicit drugs. This novel approach allows for the analysis of drugs from multiple biological fluids without sample preparation protocols. The effect of pSi-MP size, pore diameter, pore depth and functionalization on analytical performance is investigated. pSi-MPs were optimized for the rapid and high sensitivity detection of methadone, cocaine and 3,4-methylenedioxymethamphetamine (MDMA). This optimized system allowed extraction and detection of methadone from spiked saliva and clinical urine samples. Furthermore, by detecting oxycodone in additional clinical saliva and plasma samples, we were able to demonstrate the versatility of the pSi-MP SALDI-MS technique.

  16. Ion transport by gating voltage to nanopores produced via metal-assisted chemical etching method

    Science.gov (United States)

    Van Toan, Nguyen; Inomata, Naoki; Toda, Masaya; Ono, Takahito

    2018-05-01

    In this work, we report a simple and low-cost way to create nanopores that can be employed for various applications in nanofluidics. Nano sized Ag particles in the range from 1 to 20 nm are formed on a silicon substrate with a de-wetting method. Then the silicon nanopores with an approximate 15 nm average diameter and 200 μm height are successfully produced by the metal-assisted chemical etching method. In addition, electrically driven ion transport in the nanopores is demonstrated for nanofluidic applications. Ion transport through the nanopores is observed and could be controlled by an application of a gating voltage to the nanopores.

  17. Silicon-Based Nanoscale Composite Energetic Materials

    Science.gov (United States)

    2013-02-01

    1193-1211. 9. Krishnamohan, G., E.M. Kurian, and H.R. Rao, Thermal Analysis and Inverse Burning Rate Studies on Silicon-Potassium Nitrate System...reported in a journal paper and appears in the Appendix. Multiscale Nanoporous Silicon Combustion Introduction for nanoporous silicon effort While

  18. Nonsymmetric gas transfer phenomena in nanoporous media

    International Nuclear Information System (INIS)

    Kurchatov, I.M.

    2011-01-01

    The regularities of nonsymmetric gas (nitrogen, helium, hydrogen, carbon dioxide) transfer in nanoporous materials are investigated. The effects of anisotropy and hysteresis of permeability in nanoporous media with pore gradient and porosity in objects of various nature are found out. The following objects are studied: polyethylene terephthalate track membranes with asymmetric pore form, commercial polyvinyl trimethylsilane gas-separation membranes with continuous distribution of pores over the membrane thickness and porous composite membranes (born nitride, silicon carbide, aluminium oxide) prepared by self-propagating high-temperature synthesis with abrupt change of pore dimensions over the thickness. The possible mechanisms of nonsymmetric gas transfer effects are under consideration [ru

  19. 1/f noise in graphene nanopores

    International Nuclear Information System (INIS)

    Heerema, S J; Schneider, G F; Rozemuller, M; Vicarelli, L; Zandbergen, H W; Dekker, C

    2015-01-01

    Graphene nanopores are receiving great attention due to their atomically thin membranes and intrinsic electrical properties that appear greatly beneficial for biosensing and DNA sequencing. Here, we present an extensive study of the low-frequency 1/f noise in the ionic current through graphene nanopores and compare it to noise levels in silicon nitride pore currents. We find that the 1/f noise magnitude is very high for graphene nanopores: typically two orders of magnitude higher than for silicon nitride pores. This is a drawback as it significantly lowers the signal-to-noise ratio in DNA translocation experiments. We evaluate possible explanations for these exceptionally high noise levels in graphene pores. From examining the noise for pores of different diameters and at various salt concentrations, we find that in contrast to silicon nitride pores, the 1/f noise in graphene pores does not follow Hooge’s relation. In addition, from studying the dependence on the buffer pH, we show that the increased noise cannot be explained by charge fluctuations of chemical groups on the pore rim. Finally, we compare single and bilayer graphene to few-layer and multi-layer graphene and boron nitride (h-BN), and we find that the noise reduces with layer thickness for both materials, which suggests that mechanical fluctuations may be the underlying cause of the high 1/f noise levels in monolayer graphene nanopore devices. (paper)

  20. Ultra-Thin Solid-State Nanopores: Fabrication and Applications

    Science.gov (United States)

    Kuan, Aaron Tzeyang

    Solid-state nanopores are a nanofluidic platform with unique advantages for single-molecule analysis and filtration applications. However, significant improvements in device performance and scalable fabrication methods are needed to make nanopore devices competitive with existing technologies. This dissertation investigates the potential advantages of ultra-thin nanopores in which the thickness of the membrane is significantly smaller than the nanopore diameter. Novel, scalable fabrication methods were first developed and then utilized to examine device performance for water filtration and single molecule sensing applications. Fabrication of nanometer-thin pores in silicon nitride membranes was achieved using a feedback-controlled ion beam method in which ion sputtering is arrested upon detection of the first few ions that drill through the membrane. Performing fabrication at liquid nitrogen temperatures prevents surface atom rearrangements that have previously complicated similar processes. A novel cross-sectional imaging method was also developed to allow careful examination of the full nanopore geometry. Atomically-thin graphene nanopores were fabricated via an electrical pulse method in which sub-microsecond electrical pulses applied across a graphene membrane in electrolyte solution are used to create a defect in the membrane and controllably enlarge it into a nanopore. This method dramatically increases the accuracy and reliability of graphene nanopore production, allowing consistent production of single nanopores down to subnanometer sizes. In filtration applications in which nanopores are used to selectively restrict the passage of dissolved contaminants, ultra-thin nanopores minimize the flow resistance, increasing throughput and energy-efficiency. The ability of graphene nanopores to separate different ions was characterized via ionic conductance and reversal potential measurements. Graphene nanopores were observed to conduct cations preferentially over

  1. Polyhedral oligomeric silsequioxane monolayer as a nanoporous interlayer for preparation of low-k dielectric films

    International Nuclear Information System (INIS)

    Liu, Y-L; Liu, C-S; Cho, C-I; Hwu, M-J

    2007-01-01

    Polyhedral oligomeric silsequioxane (POSS) monomer was fixed to a silicon surface by reacting octakis(glycidyldimethylsiloxy)octasilsesquioxane (OG-POSS) with the OH-terminated silicon surface in the presence of tin (II) chloride. The POSS cage layer then served as a nanoporous interlayer to reduce the dielectric constants of polyimide films on silicon surfaces. The chemical structure and surface morphology of OG-POSS modified silicon surfaces were characterized with XPS. With the introduction of a POSS nanopored interlayer, the dielectric constants of polyimide films were reduced

  2. Nanoporous polymer electrolyte

    Science.gov (United States)

    Elliott, Brian [Wheat Ridge, CO; Nguyen, Vinh [Wheat Ridge, CO

    2012-04-24

    A nanoporous polymer electrolyte and methods for making the polymer electrolyte are disclosed. The polymer electrolyte comprises a crosslinked self-assembly of a polymerizable salt surfactant, wherein the crosslinked self-assembly includes nanopores and wherein the crosslinked self-assembly has a conductivity of at least 1.0.times.10.sup.-6 S/cm at 25.degree. C. The method of making a polymer electrolyte comprises providing a polymerizable salt surfactant. The method further comprises crosslinking the polymerizable salt surfactant to form a nanoporous polymer electrolyte.

  3. Nanoporous thermosetting polymers.

    Science.gov (United States)

    Raman, Vijay I; Palmese, Giuseppe R

    2005-02-15

    Potential applications of nanoporous thermosetting polymers include polyelectrolytes in fuel cells, separation membranes, adsorption media, and sensors. Design of nanoporous polymers for such applications entails controlling permeability by tailoring pore size, structure, and interface chemistry. Nanoporous thermosetting polymers are often synthesized via free radical mechanisms using solvents that phase separate during polymerization. In this work, a novel technique for the synthesis of nanoporous thermosets is presented that is based on the reactive encapsulation of an inert solvent using step-growth cross-linking polymerization without micro/macroscopic phase separation. The criteria for selecting such a monomer-polymer-solvent system are discussed based on FTIR analysis, observed micro/macroscopic phase separation, and thermodynamics of swelling. Investigation of resulting network pore structures by scanning electron microscopy (SEM) and small-angle X-ray scattering following extraction and supercritical drying using carbon dioxide showed that nanoporous polymeric materials with pore sizes ranging from 1 to 50 nm can be synthesized by varying the solvent content. The differences in the porous morphology of these materials compared to more common free radically polymerized analogues that exhibit phase separation were evident from SEM imaging. Furthermore, it was demonstrated that the chemical activity of the nanoporous materials obtained by our method could be tailored by grafting appropriate functional groups at the pore interface.

  4. Silicon nitride nanosieve membrane

    NARCIS (Netherlands)

    Tong, D.H.; Jansen, Henricus V.; Gadgil, V.J.; Bostan, C.G.; Berenschot, Johan W.; van Rijn, C.J.M.; Elwenspoek, Michael Curt

    2004-01-01

    An array of very uniform cylindrical nanopores with a pore diameter as small as 25 nm has been fabricated in an ultrathin micromachined silicon nitride membrane using focused ion beam (FIB) etching. The pore size of this nanosieve membrane was further reduced to below 10 nm by coating it with

  5. Hydrophilic nanoporous materials

    DEFF Research Database (Denmark)

    2010-01-01

    The present application discloses a method for preparing and rendering hydrophilic a nanoporous material of a polymer matrix which has a porosity of 0.1-90 percent (v/v), such that the ratio between the final water absorption (percent (w/w)) and the porosity (percent (v/v)) is at least 0.05, the ......The present application discloses a method for preparing and rendering hydrophilic a nanoporous material of a polymer matrix which has a porosity of 0.1-90 percent (v/v), such that the ratio between the final water absorption (percent (w/w)) and the porosity (percent (v/v)) is at least 0.......05, the method comprising the steps of: (a) preparing a precursor material comprising at least one polymeric component and having a first phase and a second phase; (b) removal of at least a part of the first phase of the precursor material prepared in step (a) so as to leave behind a nanoporous material...... of the polymer matrix; (c) irradiating at least a part of said nanoporous material with light of a wave length of in the range of 250-400 nm (or 200-700 nm) in the presence of oxygen and/or ozone. Corresponding hydrophilic nanoporous materials are also disclosed. L...

  6. Solid-state nanopores of controlled geometry fabricated in a transmission electron microscope

    Science.gov (United States)

    Qian, Hui; Egerton, Ray F.

    2017-11-01

    Energy-filtered transmission electron microscopy and electron tomography were applied to in situ studies of the formation, shape, and diameter of nanopores formed in a silicon nitride membrane in a transmission electron microscope. The nanopore geometry was observed in three dimensions by electron tomography. Drilling conditions, such as probe current, beam convergence angle, and probe position, affect the formation rate and the geometry of the pores. With a beam convergence semi-angle of α = 22 mrad, a conical shaped nanopore is formed but at α = 45 mrad, double-cone (hourglass-shaped) nanopores were produced. Nanopores with an effective diameter between 10 nm and 1.8 nm were fabricated by controlling the drilling time.

  7. Nanopores creation in boron and nitrogen doped polycrystalline graphene: A molecular dynamics study

    Science.gov (United States)

    Izadifar, Mohammadreza; Abadi, Rouzbeh; Nezhad Shirazi, Ali Hossein; Alajlan, Naif; Rabczuk, Timon

    2018-05-01

    In the present paper, molecular dynamic simulations have been conducted to investigate the nanopores creation on 10% of boron and nitrogen doped polycrystalline graphene by silicon and diamond nanoclusters. Two types of nanoclusters based on silicon and diamond are used to investigate their effect for the fabrication of nanopores. Therefore, three different diameter sizes of the clusters with five kinetic energies of 10, 50, 100, 300 and 500 eV/atom at four different locations in boron or nitrogen doped polycrystalline graphene nanosheets have been perused. We also study the effect of 3% and 6% of boron doped polycrystalline graphene with the best outcome from 10% of doping. Our results reveal that the diamond cluster with diameter of 2 and 2.5 nm fabricates the largest nanopore areas on boron and nitrogen doped polycrystalline graphene, respectively. Furthermore, the kinetic energies of 10 and 50 eV/atom can not fabricate nanopores in some cases for silicon and diamond clusters on boron doped polycrystalline graphene nanosheets. On the other hand, silicon and diamond clusters fabricate nanopores for all locations and all tested energies on nitrogen doped polycrystalline graphene. The area sizes of nanopores fabricated by silicon and diamond clusters with diameter of 2 and 2.5 nm are close to the actual area size of the related clusters for the kinetic energy of 300 eV/atom in all locations on boron doped polycrystalline graphene. The maximum area and the average maximum area of nanopores are fabricated by the kinetic energy of 500 eV/atom inside the grain boundary at the center of the nanosheet and in the corner of nanosheet with diameters of 2 and 3 nm for silicon and diamond clusters on boron and nitrogen doped polycrystalline graphene.

  8. Solid-State Nanopore

    Directory of Open Access Journals (Sweden)

    Zhishan Yuan

    2018-02-01

    Full Text Available Abstract Solid-state nanopore has captured the attention of many researchers due to its characteristic of nanoscale. Now, different fabrication methods have been reported, which can be summarized into two broad categories: “top-down” etching technology and “bottom-up” shrinkage technology. Ion track etching method, mask etching method chemical solution etching method, and high-energy particle etching and shrinkage method are exhibited in this report. Besides, we also discussed applications of solid-state nanopore fabrication technology in DNA sequencing, protein detection, and energy conversion.

  9. Structure of poly(di-n-hexylsilane) in nanoporous materials

    International Nuclear Information System (INIS)

    Korotkova, I.; Sakhno, T.; Drobit'ko, I.; Sakhno, Yu.; Ostapenko, N.

    2010-01-01

    Graphical abstract: On the basis of theoretical calculations using TD/CEP-31G method we found and interpreted the complexation mechanism of poly(di-n-hexylsilane) incorporated in nanoporous materials. - Abstract: In this work the effects of solvent polarity and conformation changing on the electronic characteristics of poly(di-n-hexylsilane) incorporated in the nanoporous materials are calculated. The dependence of energy levels of electronic-excited states of investigated compounds is analyzed as a function of the Si-Si-Si-Si twist angle and length of Si-Si and Si-C bonds. The possibility of complex formation between silicon atom of polymer and oxygen ions of nanoporous materials is shown.

  10. Controllable Shrinking of Glass Capillary Nanopores Down to sub-10 nm by Wet-Chemical Silanization for Signal-Enhanced DNA Translocation.

    Science.gov (United States)

    Xu, Xiaolong; Li, Chuanping; Zhou, Ya; Jin, Yongdong

    2017-10-27

    Diameter is a major concern for nanopore based sensing. However, directly pulling glass capillary nanopore with diameter down to sub-10 nm is very difficult. So, post treatment is sometimes necessary. Herein, we demonstrate a facile and effective wet-chemical method to shrink the diameter of glass capillary nanopore from several tens of nanometers to sub-10 nm by disodium silicate hydrolysis. Its benefits for DNA translocation are investigated. The shrinking of glass capillary nanopore not only slows down DNA translocation, but also enhances DNA translocation signal and signal-to-noise ratio significantly (102.9 for 6.4 nm glass nanopore, superior than 15 for a 3 nm silicon nitride nanopore). It also affects DNA translocation behaviors, making the approach and glass capillary nanopore platform promising for DNA translocation studies.

  11. Ion current rectification, limiting and overlimiting conductances in nanopores.

    Directory of Open Access Journals (Sweden)

    Liesbeth van Oeffelen

    Full Text Available Previous reports on Poisson-Nernst-Planck (PNP simulations of solid-state nanopores have focused on steady state behaviour under simplified boundary conditions. These are Neumann boundary conditions for the voltage at the pore walls, and in some cases also Donnan equilibrium boundary conditions for concentrations and voltages at both entrances of the nanopore. In this paper, we report time-dependent and steady state PNP simulations under less restrictive boundary conditions, including Neumann boundary conditions applied throughout the membrane relatively far away from the nanopore. We simulated ion currents through cylindrical and conical nanopores with several surface charge configurations, studying the spatial and temporal dependence of the currents contributed by each ion species. This revealed that, due to slow co-diffusion of oppositely charged ions, steady state is generally not reached in simulations or in practice. Furthermore, it is shown that ion concentration polarization is responsible for the observed limiting conductances and ion current rectification in nanopores with asymmetric surface charges or shapes. Hence, after more than a decade of collective research attempting to understand the nature of ion current rectification in solid-state nanopores, a relatively intuitive model is retrieved. Moreover, we measured and simulated current-voltage characteristics of rectifying silicon nitride nanopores presenting overlimiting conductances. The similarity between measurement and simulation shows that overlimiting conductances can result from the increased conductance of the electric double-layer at the membrane surface at the depletion side due to voltage-induced polarization charges. The MATLAB source code of the simulation software is available via the website http://micr.vub.ac.be.

  12. Nanopore sensors for DNA analysis

    DEFF Research Database (Denmark)

    Solovyeva, Vita; Venkatesan, B.M.; Shim, Jeong

    2012-01-01

    Solid-state nanopore sensors are promising devices for single DNA molecule detection and sequencing. This paper presents a review of our work on solid-state nanopores performed over the last decade. In particular, here we discuss atomic-layer-deposited (ALD)-based, graphene-based, and functionali......Solid-state nanopore sensors are promising devices for single DNA molecule detection and sequencing. This paper presents a review of our work on solid-state nanopores performed over the last decade. In particular, here we discuss atomic-layer-deposited (ALD)-based, graphene...

  13. Nanoscale volcanoes: accretion of matter at ion-sculpted nanopores.

    Science.gov (United States)

    Mitsui, Toshiyuki; Stein, Derek; Kim, Young-Rok; Hoogerheide, David; Golovchenko, J A

    2006-01-27

    We demonstrate the formation of nanoscale volcano-like structures induced by ion-beam irradiation of nanoscale pores in freestanding silicon nitride membranes. Accreted matter is delivered to the volcanoes from micrometer distances along the surface. Volcano formation accompanies nanopore shrinking and depends on geometrical factors and the presence of a conducting layer on the membrane's back surface. We argue that surface electric fields play an important role in accounting for the experimental observations.

  14. Optimized nanoporous materials.

    Energy Technology Data Exchange (ETDEWEB)

    Braun, Paul V. (University of Illinois at Urbana-Champaign, Urbana, IL); Langham, Mary Elizabeth; Jacobs, Benjamin W.; Ong, Markus D.; Narayan, Roger J. (North Carolina State University, Raleigh, NC); Pierson, Bonnie E. (North Carolina State University, Raleigh, NC); Gittard, Shaun D. (North Carolina State University, Raleigh, NC); Robinson, David B.; Ham, Sung-Kyoung (Korea Basic Science Institute, Gangneung, South Korea); Chae, Weon-Sik (Korea Basic Science Institute, Gangneung, South Korea); Gough, Dara V. (University of Illinois at Urbana-Champaign, Urbana, IL); Wu, Chung-An Max; Ha, Cindy M.; Tran, Kim L.

    2009-09-01

    Nanoporous materials have maximum practical surface areas for electrical charge storage; every point in an electrode is within a few atoms of an interface at which charge can be stored. Metal-electrolyte interfaces make best use of surface area in porous materials. However, ion transport through long, narrow pores is slow. We seek to understand and optimize the tradeoff between capacity and transport. Modeling and measurements of nanoporous gold electrodes has allowed us to determine design principles, including the fact that these materials can deplete salt from the electrolyte, increasing resistance. We have developed fabrication techniques to demonstrate architectures inspired by these principles that may overcome identified obstacles. A key concept is that electrodes should be as close together as possible; this is likely to involve an interpenetrating pore structure. However, this may prove extremely challenging to fabricate at the finest scales; a hierarchically porous structure can be a worthy compromise.

  15. Photovoltaic characteristics of porous silicon /(n+ - p) silicon solar cells

    International Nuclear Information System (INIS)

    Dzhafarov, T.D.; Aslanov, S.S.; Ragimov, S.H.; Sadigov, M.S.; Nabiyeva, A.F.; Yuksel, Aydin S.

    2012-01-01

    Full text : The purpose of this work is to improve the photovoltaic parameters of the screen-printed silicon solar cells by formation the nano-porous silicon film on the frontal surface of the cell. The photovoltaic characteristics of two type silicon solar cells with and without porous silicon layer were measured and compared. A remarkable increment of short-circuit current density and the efficiency by 48 percent and 20 percent, respectively, have been achieved for PS/(n + - pSi) solar cell comparing to (n + - p)Si solar cell without PS layer

  16. Rapid manufacturing of low-noise membranes for nanopore sensors by trans-chip illumination lithography

    International Nuclear Information System (INIS)

    Janssen, Xander J A; Jonsson, Magnus P; Plesa, Calin; Soni, Gautam V; Dekker, Cees; Dekker, Nynke H

    2012-01-01

    In recent years, the concept of nanopore sensing has matured from a proof-of-principle method to a widespread, versatile technique for the study of biomolecular properties and interactions. While traditional nanopore devices based on a nanopore in a single layer membrane supported on a silicon chip can be rapidly fabricated using standard microfabrication methods, chips with additional insulating layers beyond the membrane region can provide significantly lower noise levels, but at the expense of requiring more costly and time-consuming fabrication steps. Here we present a novel fabrication protocol that overcomes this issue by enabling rapid and reproducible manufacturing of low-noise membranes for nanopore experiments. The fabrication protocol, termed trans-chip illumination lithography, is based on illuminating a membrane-containing wafer from its backside such that a photoresist (applied on the wafer’s top side) is exposed exclusively in the membrane regions. Trans-chip illumination lithography permits the local modification of membrane regions and hence the fabrication of nanopore chips containing locally patterned insulating layers. This is achieved while maintaining a well-defined area containing a single thin membrane for nanopore drilling. The trans-chip illumination lithography method achieves this without relying on separate masks, thereby eliminating time-consuming alignment steps as well as the need for a mask aligner. Using the presented approach, we demonstrate rapid and reproducible fabrication of nanopore chips that contain small (12 μm × 12 μm) free-standing silicon nitride membranes surrounded by insulating layers. The electrical noise characteristics of these nanopore chips are shown to be superior to those of simpler designs without insulating layers and comparable in quality to more complex designs that are more challenging to fabricate. (paper)

  17. Nanofluidic Device with Embedded Nanopore

    Science.gov (United States)

    Zhang, Yuning; Reisner, Walter

    2014-03-01

    Nanofluidic based devices are robust methods for biomolecular sensing and single DNA manipulation. Nanopore-based DNA sensing has attractive features that make it a leading candidate as a single-molecule DNA sequencing technology. Nanochannel based extension of DNA, combined with enzymatic or denaturation-based barcoding schemes, is already a powerful approach for genome analysis. We believe that there is revolutionary potential in devices that combine nanochannels with nanpore detectors. In particular, due to the fast translocation of a DNA molecule through a standard nanopore configuration, there is an unfavorable trade-off between signal and sequence resolution. With a combined nanochannel-nanopore device, based on embedding a nanopore inside a nanochannel, we can in principle gain independent control over both DNA translocation speed and sensing signal, solving the key draw-back of the standard nanopore configuration. We demonstrate that we can detect - using fluorescent microscopy - successful translocation of DNA from the nanochannel out through the nanopore, a possible method to 'select' a given barcode for further analysis. We also show that in equilibrium DNA will not escape through an embedded sub-persistence length nanopore until a certain voltage bias is added.

  18. Catalytic nanoporous membranes

    Science.gov (United States)

    Pellin, Michael J; Hryn, John N; Elam, Jeffrey W

    2013-08-27

    A nanoporous catalytic membrane which displays several unique features Including pores which can go through the entire thickness of the membrane. The membrane has a higher catalytic and product selectivity than conventional catalysts. Anodic aluminum oxide (AAO) membranes serve as the catalyst substrate. This substrate is then subjected to Atomic Layer Deposition (ALD), which allows the controlled narrowing of the pores from 40 nm to 10 nm in the substrate by deposition of a preparatory material. Subsequent deposition of a catalytic layer on the inner surfaces of the pores reduces pore sizes to less than 10 nm and allows for a higher degree of reaction selectivity. The small pore sizes allow control over which molecules enter the pores, and the flow-through feature can allow for partial oxidation of reactant species as opposed to complete oxidation. A nanoporous separation membrane, produced by ALD is also provided for use in gaseous and liquid separations. The membrane has a high flow rate of material with 100% selectivity. Also provided is a method for producing a catalytic membrane having flow-through pores and discreet catalytic clusters adhering to the inside surfaces of the pores.

  19. Nanoporous Anodic Alumina: A Versatile Platform for Optical Biosensors

    Directory of Open Access Journals (Sweden)

    Abel Santos

    2014-05-01

    Full Text Available Nanoporous anodic alumina (NAA has become one of the most promising nanomaterials in optical biosensing as a result of its unique physical and chemical properties. Many studies have demonstrated the outstanding capabilities of NAA for developing optical biosensors in combination with different optical techniques. These results reveal that NAA is a promising alternative to other widely explored nanoporous platforms, such as porous silicon. This review is aimed at reporting on the recent advances and current stage of development of NAA-based optical biosensing devices. The different optical detection techniques, principles and concepts are described in detail along with relevant examples of optical biosensing devices using NAA sensing platforms. Furthermore, we summarise the performance of these devices and provide a future perspective on this promising research field.

  20. Highly sensitive detection using microring resonator and nanopores

    Science.gov (United States)

    Bougot-Robin, K.; Hoste, J. W.; Le Thomas, N.; Bienstman, P.; Edel, J. B.

    2016-04-01

    One of the most significant challenges facing physical and biological scientists is the accurate detection and identification of single molecules in free-solution environments. The ability to perform such sensitive and selective measurements opens new avenues for a large number of applications in biological, medical and chemical analysis, where small sample volumes and low analyte concentrations are the norm. Access to information at the single or few molecules scale is rendered possible by a fine combination of recent advances in technologies. We propose a novel detection method that combines highly sensitive label-free resonant sensing obtained with high-Q microcavities and position control in nanoscale pores (nanopores). In addition to be label-free and highly sensitive, our technique is immobilization free and does not rely on surface biochemistry to bind probes on a chip. This is a significant advantage, both in term of biology uncertainties and fewer biological preparation steps. Through combination of high-Q photonic structures with translocation through nanopore at the end of a pipette, or through a solid-state membrane, we believe significant advances can be achieved in the field of biosensing. Silicon microrings are highly advantageous in term of sensitivity, multiplexing, and microfabrication and are chosen for this study. In term of nanopores, we both consider nanopore at the end of a nanopipette, with the pore being approach from the pipette with nanoprecise mechanical control. Alternatively, solid state nanopores can be fabricated through a membrane, supporting the ring. Both configuration are discussed in this paper, in term of implementation and sensitivity.

  1. Nanoporous polymer liquid core waveguides

    DEFF Research Database (Denmark)

    Gopalakrishnan, Nimi; Christiansen, Mads Brøkner; Ndoni, Sokol

    2010-01-01

    We demonstrate liquid core waveguides defined by UV to enable selective water infiltration in nanoporous polymers, creating an effective refractive index shift Δn=0.13. The mode confinement and propagation loss in these waveguides are presented.......We demonstrate liquid core waveguides defined by UV to enable selective water infiltration in nanoporous polymers, creating an effective refractive index shift Δn=0.13. The mode confinement and propagation loss in these waveguides are presented....

  2. Highly active thermally stable nanoporous gold catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Biener, Juergen; Wittstock, Arne; Biener, Monika M.; Bagge-Hansen, Michael; Baeumer, Marcus; Wichmann, Andre; Neuman, Bjoern

    2016-12-20

    In one embodiment, a system includes a nanoporous gold structure and a plurality of oxide particles deposited on the nanoporous gold structure; the oxide particles are characterized by a crystalline phase. In another embodiment, a method includes depositing oxide nanoparticles on a nanoporous gold support to form an active structure and functionalizing the deposited oxide nanoparticles.

  3. Track-etched nanopores in spin-coated polycarbonate films applied as sputtering mask

    International Nuclear Information System (INIS)

    Nix, A.-K.; Gehrke, H.-G.; Krauser, J.; Trautmann, C.; Weidinger, A.; Hofsaess, H.

    2009-01-01

    Thin polycarbonate films were spin-coated on silicon substrates and subsequently irradiated with 1-GeV U ions. The ion tracks in the polymer layer were chemically etched yielding nanopores of about 40 nm diameter. In a second process, the nanoporous polymer film acted as mask for structuring the Si substrate underneath. Sputtering with 5-keV Xe ions produced surface craters of depth ∼150 nm and diameter ∼80 nm. This arrangement can be used for the fabrication of track-based nanostructures with self-aligned apertures.

  4. Vertically aligned nanowires on flexible silicone using a supported alumina template prepared by pulsed anodization

    DEFF Research Database (Denmark)

    Mátéfi-Tempfli, Stefan; Mátéfi-Tempfli, M.

    2009-01-01

    Carpets of vertically aligned nanowires on flexible substrates are successfully realized by a template method. Applying special pulsed anodization conditions, defect-free nanoporous alumina structures supported on polydimethylsiloxane (PDMS), a flexible silicone elastomer, are created. By using...... this template with nanopores ending on a conducting underlayer, a high-density nanowire array can be simply grown by direct DCelectrodeposition on the top of the silicone rubber....

  5. The controlled fabrication of nanopores by focused electron-beam-induced etching

    International Nuclear Information System (INIS)

    Yemini, M; Ashkenasy, N; Hadad, B; Goldner, A; Liebes, Y

    2009-01-01

    The fabrication of nanometric holes within thin silicon-based membranes is of great importance for various nanotechnology applications. The preparation of such holes with accurate control over their size and shape is, thus, gaining a lot of interest. In this work we demonstrate the use of a focused electron-beam-induced etching (FEBIE) process as a promising tool for the fabrication of such nanopores in silicon nitride membranes and study the process parameters. The reduction of silicon nitride by the electron beam followed by chemical etching of the residual elemental silicon results in a linear dependence of pore diameter on electron beam exposure time, enabling accurate control of nanopore size in the range of 17-200 nm in diameter. An optimal pressure of 5.3 x 10 -6 Torr for the production of smaller pores with faster process rates, as a result of mass transport effects, was found. The pore formation process is also shown to be dependent on the details of the pulsed process cycle, which control the rate of the pore extension, and its minimal and maximal size. Our results suggest that the FEBIE process may play a key role in the fabrication of nanopores for future devices both in sensing and nano-electronics applications.

  6. Soft matter in hard confinement: phase transition thermodynamics, structure, texture, diffusion and flow in nanoporous media

    Science.gov (United States)

    Huber, Patrick

    2015-03-01

    Spatial confinement in nanoporous media affects the structure, thermodynamics and mobility of molecular soft matter often markedly. This article reviews thermodynamic equilibrium phenomena, such as physisorption, capillary condensation, crystallisation, self-diffusion, and structural phase transitions as well as selected aspects of the emerging field of spatially confined, non-equilibrium physics, i.e. the rheology of liquids, capillarity-driven flow phenomena, and imbibition front broadening in nanoporous materials. The observations in the nanoscale systems are related to the corresponding bulk phenomenologies. The complexity of the confined molecular species is varied from simple building blocks, like noble gas atoms, normal alkanes and alcohols to liquid crystals, polymers, ionic liquids, proteins and water. Mostly, experiments with mesoporous solids of alumina, gold, carbon, silica, and silicon with pore diameters ranging from a few up to 50 nm are presented. The observed peculiarities of nanopore-confined condensed matter are also discussed with regard to applications. A particular emphasis is put on texture formation upon crystallisation in nanoporous media, a topic both of high fundamental interest and of increasing nanotechnological importance, e.g. for the synthesis of organic/inorganic hybrid materials by melt infiltration, the usage of nanoporous solids in crystal nucleation or in template-assisted electrochemical deposition of nano structures.

  7. Stepwise Nanopore Evolution in One-Dimensional Nanostructures

    KAUST Repository

    Choi, Jang Wook

    2010-04-14

    We report that established simple lithium (Li) ion battery cycles can be used to produce nanopores inside various useful one-dimensional (1D) nanostructures such as zinc oxide, silicon, and silver nanowires. Moreover, porosities of these 1D nanomaterials can be controlled in a stepwise manner by the number of Li-battery cycles. Subsequent pore characterization at the end of each cycle allows us to obtain detailed snapshots of the distinct pore evolution properties in each material due to their different atomic diffusion rates and types of chemical bonds. Also, this stepwise characterization led us to the first observation of pore size increases during cycling, which can be interpreted as a similar phenomenon to Ostwald ripening in analogous nanoparticle cases. Finally, we take advantage of the unique combination of nanoporosity and 1D materials and demonstrate nanoporous silicon nanowires (poSiNWs) as excellent supercapacitor (SC) electrodes in high power operations compared to existing devices with activated carbon. © 2010 American Chemical Society.

  8. Biodegradable nanoporous nanoparticles for human serum analysis

    International Nuclear Information System (INIS)

    Pujia, A.; De Angelis, F.; Scumaci, D.; Gaspari, M.; Liberale, C.; Candeloro, P.; Cuda, G.; Di Fabrizio, E.

    2010-01-01

    Modern medicine and biology search for new powerful tool for biomarkers discovery, appears one of the most promising approaches for early cancer diagnosis. Nowadays, the low molecular weight fraction of human serum is the most informative source of biomarkers, but their study and identification are very difficult due to the incredible complexity of the raw human serum. In this work we describe a novel tool for the filtration of crude human serum or other bio-fluid based on water soluble nanoparticles. Nanoparticles with a pore size of about 2-3 nm, and diameters of 200 nm were obtained by ultrasonication of nanoporous silicon. The porous nanoparticles act as a nanosieve able to exclusively harvest the low molecular weight fraction of the fluid thanks to a controllable pore size. After a short incubation, the infiltrated nanosieves can be extracted from the starting fluid by means of centrifugation, and dissolved in water in a few minutes to give the captured molecules back in their native state, without degradation and contamination. The raw fluid is so split in two components of high and low molecular weight, that are both available for further analyses with any other investigation technique. Here, fluorescence spectroscopy, 2D-gel electrophoresis, and mass spectrometry are exploited to show the split of different bio-fluids under physiological condition. A cut-off (or split level) of 13 kDa is demonstrated also for human serum.

  9. Nanoporous Polymeric Grating-Based Biosensors

    KAUST Repository

    Gao, Tieyu

    2012-05-02

    We demonstrate the utilization of an interferometrically created nanoporous polymeric gratings as a platform for biosensing applications. Aminopropyltriethoxysilane (APTES)-functionalized nanoporous polymeric gratings was fabricated by combining holographic interference patterning and APTES-functionalization of pre-polymer syrup. The successful detection of multiple biomolecules indicates that the biofunctionalized nanoporous polymeric gratings can act as biosensing platforms which are label-free, inexpensive, and applicable as high-throughput assays. Copyright © 2010 by ASME.

  10. Nanoporous Polymeric Grating-Based Biosensors

    KAUST Repository

    Gao, Tieyu; Hsiao, Vincent; Zheng, Yue Bing; Huang, Tony Jun

    2012-01-01

    We demonstrate the utilization of an interferometrically created nanoporous polymeric gratings as a platform for biosensing applications. Aminopropyltriethoxysilane (APTES)-functionalized nanoporous polymeric gratings was fabricated by combining holographic interference patterning and APTES-functionalization of pre-polymer syrup. The successful detection of multiple biomolecules indicates that the biofunctionalized nanoporous polymeric gratings can act as biosensing platforms which are label-free, inexpensive, and applicable as high-throughput assays. Copyright © 2010 by ASME.

  11. Optical detection of two-color-fluorophore barcode for nanopore DNA sensing

    Science.gov (United States)

    Zhang, M.; Sychugov, I.; Schmidt, T.; Linnros, J.

    2015-06-01

    A simple schematic on parallel optical detection of two-fluorophore barcode for single-molecule nanopore sensing is presented. The chosen two fluorophores, ATTO-532 and DY-521-XL, emitting in well-separated spectrum range can be excited at the same wavelength. A beam splitter was employed to separate signals from the two fluorophores and guide them to the same CCD camera. Based on a conventional microscope, sources of background in the nanopore sensing system, including membranes, compounds in buffer solution, and a detection cell was characterized. By photoluminescence excitation measurements, it turned out that silicon membrane has a negligible photoluminescence under the examined excitation from 440 nm to 560 nm, in comparison with a silicon nitrite membrane. Further, background signals from the detection cell were suppressed. Brownian motion of 450 bps DNA labelled with single ATTO-532 or DY-521-XL was successfully recorded by our optical system.

  12. Pt–Al2O3 dual layer atomic layer deposition coating in high aspect ratio nanopores

    International Nuclear Information System (INIS)

    Pardon, Gaspard; Gatty, Hithesh K; Stemme, Göran; Wijngaart, Wouter van der; Roxhed, Niclas

    2013-01-01

    Functional nanoporous materials are promising for a number of applications ranging from selective biofiltration to fuel cell electrodes. This work reports the functionalization of nanoporous membranes using atomic layer deposition (ALD). ALD is used to conformally deposit platinum (Pt) and aluminum oxide (Al 2 O 3 ) on Pt in nanopores to form a metal–insulator stack inside the nanopore. Deposition of these materials inside nanopores allows the addition of extra functionalities to nanoporous materials such as anodic aluminum oxide (AAO) membranes. Conformal deposition of Pt on such materials enables increased performances for electrochemical sensing applications or fuel cell electrodes. An additional conformal Al 2 O 3 layer on such a Pt film forms a metal–insulator–electrolyte system, enabling field effect control of the nanofluidic properties of the membrane. This opens novel possibilities in electrically controlled biofiltration. In this work, the deposition of these two materials on AAO membranes is investigated theoretically and experimentally. Successful process parameters are proposed for a reliable and cost-effective conformal deposition on high aspect ratio three-dimensional nanostructures. A device consisting of a silicon chip supporting an AAO membrane of 6 mm diameter and 1.3 μm thickness with 80 nm diameter pores is fabricated. The pore diameter is reduced to 40 nm by a conformal deposition of 11 nm Pt and 9 nm Al 2 O 3 using ALD. (paper)

  13. Pt-Al{sub 2}O{sub 3} dual layer atomic layer deposition coating in high aspect ratio nanopores

    Energy Technology Data Exchange (ETDEWEB)

    Pardon, Gaspard; Gatty, Hithesh K; Stemme, Goeran; Wijngaart, Wouter van der; Roxhed, Niclas [KTH Royal Institute of Technology, School of Electrical Engineering, Micro and Nanosystems, Osquldas Vaeg 10, SE-10044 Stockholm (Sweden)

    2013-01-11

    Functional nanoporous materials are promising for a number of applications ranging from selective biofiltration to fuel cell electrodes. This work reports the functionalization of nanoporous membranes using atomic layer deposition (ALD). ALD is used to conformally deposit platinum (Pt) and aluminum oxide (Al{sub 2}O{sub 3}) on Pt in nanopores to form a metal-insulator stack inside the nanopore. Deposition of these materials inside nanopores allows the addition of extra functionalities to nanoporous materials such as anodic aluminum oxide (AAO) membranes. Conformal deposition of Pt on such materials enables increased performances for electrochemical sensing applications or fuel cell electrodes. An additional conformal Al{sub 2}O{sub 3} layer on such a Pt film forms a metal-insulator-electrolyte system, enabling field effect control of the nanofluidic properties of the membrane. This opens novel possibilities in electrically controlled biofiltration. In this work, the deposition of these two materials on AAO membranes is investigated theoretically and experimentally. Successful process parameters are proposed for a reliable and cost-effective conformal deposition on high aspect ratio three-dimensional nanostructures. A device consisting of a silicon chip supporting an AAO membrane of 6 mm diameter and 1.3 {mu}m thickness with 80 nm diameter pores is fabricated. The pore diameter is reduced to 40 nm by a conformal deposition of 11 nm Pt and 9 nm Al{sub 2}O{sub 3} using ALD. (paper)

  14. Pt-Al2O3 dual layer atomic layer deposition coating in high aspect ratio nanopores

    Science.gov (United States)

    Pardon, Gaspard; Gatty, Hithesh K.; Stemme, Göran; van der Wijngaart, Wouter; Roxhed, Niclas

    2013-01-01

    Functional nanoporous materials are promising for a number of applications ranging from selective biofiltration to fuel cell electrodes. This work reports the functionalization of nanoporous membranes using atomic layer deposition (ALD). ALD is used to conformally deposit platinum (Pt) and aluminum oxide (Al2O3) on Pt in nanopores to form a metal-insulator stack inside the nanopore. Deposition of these materials inside nanopores allows the addition of extra functionalities to nanoporous materials such as anodic aluminum oxide (AAO) membranes. Conformal deposition of Pt on such materials enables increased performances for electrochemical sensing applications or fuel cell electrodes. An additional conformal Al2O3 layer on such a Pt film forms a metal-insulator-electrolyte system, enabling field effect control of the nanofluidic properties of the membrane. This opens novel possibilities in electrically controlled biofiltration. In this work, the deposition of these two materials on AAO membranes is investigated theoretically and experimentally. Successful process parameters are proposed for a reliable and cost-effective conformal deposition on high aspect ratio three-dimensional nanostructures. A device consisting of a silicon chip supporting an AAO membrane of 6 mm diameter and 1.3 μm thickness with 80 nm diameter pores is fabricated. The pore diameter is reduced to 40 nm by a conformal deposition of 11 nm Pt and 9 nm Al2O3 using ALD.

  15. Threading DNA through nanopores for biosensing applications

    International Nuclear Information System (INIS)

    Fyta, Maria

    2015-01-01

    This review outlines the recent achievements in the field of nanopore research. Nanopores are typically used in single-molecule experiments and are believed to have a high potential to realize an ultra-fast and very cheap genome sequencer. Here, the various types of nanopore materials, ranging from biological to 2D nanopores are discussed together with their advantages and disadvantages. These nanopores can utilize different protocols to read out the DNA nucleobases. Although, the first nanopore devices have reached the market, many still have issues which do not allow a full realization of a nanopore sequencer able to sequence the human genome in about a day. Ways to control the DNA, its dynamics and speed as the biomolecule translocates the nanopore in order to increase the signal-to-noise ratio in the reading-out process are examined in this review. Finally, the advantages, as well as the drawbacks in distinguishing the DNA nucleotides, i.e., the genetic information, are presented in view of their importance in the field of nanopore sequencing. (topical review)

  16. A nanoporous gold membrane for sensing applications

    Directory of Open Access Journals (Sweden)

    Swe Zin Oo

    2016-03-01

    Full Text Available Design and fabrication of three-dimensionally structured, gold membranes containing hexagonally close-packed microcavities with nanopores in the base, are described. Our aim is to create a nanoporous structure with localized enhancement of the fluorescence or Raman scattering at, and in the nanopore when excited with light of approximately 600 nm, with a view to provide sensitive detection of biomolecules. A range of geometries of the nanopore integrated into hexagonally close-packed assemblies of gold micro-cavities was first evaluated theoretically. The optimal size and shape of the nanopore in a single microcavity were then considered to provide the highest localized plasmon enhancement (of fluorescence or Raman scattering at the very center of the nanopore for a bioanalyte traversing through. The optimized design was established to be a 1200 nm diameter cavity of 600 nm depth with a 50 nm square nanopore with rounded corners in the base. A gold 3D-structured membrane containing these sized microcavities with the integrated nanopore was successfully fabricated and ‘proof of concept’ Raman scattering experiments are described. Keywords: Nanopore, Polymer sphere, Gold membrane, Plasmons, Sensing, SERS

  17. Influence of Nanopore Shapes on Thermal Conductivity of Two-Dimensional Nanoporous Material.

    Science.gov (United States)

    Huang, Cong-Liang; Huang, Zun; Lin, Zi-Zhen; Feng, Yan-Hui; Zhang, Xin-Xin; Wang, Ge

    2016-12-01

    The influence of nanopore shapes on the electronic thermal conductivity (ETC) was studied in this paper. It turns out that with same porosity, the ETC will be quite different for different nanopore shapes, caused by the different channel width for different nanopore shapes. With same channel width, the influence of different nanopore shapes can be approximately omitted if the nanopore is small enough (smaller than 0.5 times EMFP in this paper). The ETC anisotropy was discovered for triangle nanopores at a large porosity with a large nanopore size, while there is a similar ETC for small pore size. It confirmed that the structure difference for small pore size may not be seen by electrons in their moving.

  18. On the specific surface area of nanoporous materials

    NARCIS (Netherlands)

    Detsi, E.; De Jong, E.; Zinchenko, A.; Vukovic, Z.; Vukovic, I.; Punzhin, S.; Loos, K.; ten Brinke, G.; De Raedt, H. A.; Onck, P. R.; De Hosson, J. T. M.

    2011-01-01

    A proper quantification of the specific surface area of nanoporous materials is necessary for a better understanding of the properties that are affected by the high surface-area-to-volume ratio of nanoporous metals, nanoporous polymers and nanoporous ceramics. In this paper we derive an analytical

  19. UV Defined Nanoporous Liquid Core Waveguides

    DEFF Research Database (Denmark)

    Christiansen, Mads Brøkner; Gopalakrishnan, Nimi; Ndoni, Sokol

    2011-01-01

    Nanoporous liquid core waveguides, where both core and cladding are made from the same material, are presented. The nanoporous polymer used is intrinsically hydrophobic, but selective UV exposure enables it to infiltrate with an aqueous solution, thus raising the refractive index from 1.26 to 1...

  20. Gyroid nanoporous scaffold for conductive polymers

    DEFF Research Database (Denmark)

    Guo, Fengxiao; Schulte, Lars; Zhang, Weimin

    2011-01-01

    Conductive nanoporous polymers with interconnected large surface area have been prepared by depositing polypyrrole onto nanocavity walls of nanoporous 1,2-polybutadiene films with gyroid morphology. Vapor phase polymerization of pyrrole was used to generate ultrathin films and prevent pore blocking...

  1. Nanopore sensors : From hybrid to abiotic systems

    NARCIS (Netherlands)

    Kocer, Armagan; Tauk, Lara; Dejardin, Philippe

    2012-01-01

    The use of nanopores of well controlled geometry for sensing molecules in solution is reviewed. Focus is concentrated especially on synthetic track-etch pores in polymer foils and on biological nanopores, i.e. ion channels. After a brief section about multipore sensors, specific attention is

  2. Nanoporous metals for advanced energy technologies

    CERN Document Server

    Ding, Yi

    2016-01-01

    This book covers the state-of-the-art research in nanoporous metals for potential applications in advanced energy fields, including proton exchange membrane fuel cells, Li batteries (Li ion, Li-S, and Li-O2), and supercapacitors. The related structural design and performance of nanoporous metals as well as possible mechanisms and challenges are fully addressed. The formation mechanisms of nanoporous metals during dealloying, the microstructures of nanoporous metals and characterization methods, as well as miscrostructural regulation of nanoporous metals through alloy design of precursors and surface diffusion control are also covered in detail. This is an ideal book for researchers, engineers, graduate students, and government/industry officers who are in charge of R&D investments and strategy related to energy technologies.

  3. Nanopores formed by DNA origami: a review.

    Science.gov (United States)

    Bell, Nicholas A W; Keyser, Ulrich F

    2014-10-01

    Nanopores have emerged over the past two decades to become an important technique in single molecule experimental physics and biomolecule sensing. Recently DNA nanotechnology, in particular DNA origami, has been used for the formation of nanopores in insulating materials. DNA origami is a very attractive technique for the formation of nanopores since it enables the construction of 3D shapes with precise control over geometry and surface functionality. DNA origami has been applied to nanopore research by forming hybrid architectures with solid state nanopores and by direct insertion into lipid bilayers. This review discusses recent experimental work in this area and provides an outlook for future avenues and challenges. Copyright © 2014 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

  4. Design and fabrication of a 3D-structured gold film with nanopores for local electric field enhancement in the pore

    International Nuclear Information System (INIS)

    Grant-Jacob, James A; Zin Oo, Swe; Carpignano, Francesca; Brocklesby, William S; Melvin, Tracy; Boden, Stuart A; Charlton, Martin D B

    2016-01-01

    Three-dimensionally structured gold membrane films with nanopores of defined, periodic geometries are designed and fabricated to provide the spatially localised enhancement of electric fields by manipulation of the plasmons inside nanopores. Square nanopores of different size and orientation relative to the pyramid are considered for films in aqueous and air environments, which allow for control of the position of electric fields within the structure. Designs suitable for use with 780 nm light were created. Here, periodic pyramidal cavities produced by potassium hydroxide etching to the {111} planes of (100) silicon substrates are used as templates for creating a periodic, pyramidal structured, free-standing thin gold film. Consistent with the findings from the theoretical studies, a nano-sized hole of 50 nm square was milled through the gold film at a specific location in the cavity to provide electric field control which can subsequently used for enhancement of fluorescence or Raman scattering of molecules in the nanopore. (paper)

  5. Design and fabrication of a 3D-structured gold film with nanopores for local electric field enhancement in the pore

    Science.gov (United States)

    Grant-Jacob, James A.; Zin Oo, Swe; Carpignano, Francesca; Boden, Stuart A.; Brocklesby, William S.; Charlton, Martin D. B.; Melvin, Tracy

    2016-02-01

    Three-dimensionally structured gold membrane films with nanopores of defined, periodic geometries are designed and fabricated to provide the spatially localised enhancement of electric fields by manipulation of the plasmons inside nanopores. Square nanopores of different size and orientation relative to the pyramid are considered for films in aqueous and air environments, which allow for control of the position of electric fields within the structure. Designs suitable for use with 780 nm light were created. Here, periodic pyramidal cavities produced by potassium hydroxide etching to the {111} planes of (100) silicon substrates are used as templates for creating a periodic, pyramidal structured, free-standing thin gold film. Consistent with the findings from the theoretical studies, a nano-sized hole of 50 nm square was milled through the gold film at a specific location in the cavity to provide electric field control which can subsequently used for enhancement of fluorescence or Raman scattering of molecules in the nanopore.

  6. Fluoride-induced modulation of ionic transport in asymmetric nanopores functionalized with "caged" fluorescein moieties.

    Science.gov (United States)

    Ali, Mubarak; Ahmed, Ishtiaq; Ramirez, Patricio; Nasir, Saima; Cervera, Javier; Niemeyer, Christof M; Ensinger, Wolfgang

    2016-04-28

    We demonstrate experimentally and theoretically a nanofluidic fluoride sensing device based on a single conical pore functionalized with "caged" fluorescein moieties. The nanopore functionalization is based on an amine-terminated fluorescein whose phenolic hydroxyl groups are protected with tert-butyldiphenylsilyl (TBDPS) moieties. The protected fluorescein (Fcn-TBDPS-NH2) molecules are then immobilized on the nanopore surface via carbodiimide coupling chemistry. Exposure to fluoride ions removes the uncharged TBDPS moieties due to the fluoride-promoted cleavage of the silicon-oxygen bond, leading to the generation of negatively charged groups on the fluorescein moieties immobilized onto the pore surface. The asymmetrical distribution of these groups along the conical nanopore leads to the electrical rectification observed in the current-voltage (I-V) curve. On the contrary, other halides and anions are not able to induce any significant ionic rectification in the asymmetric pore. In each case, the success of the chemical functionalization and deprotection reactions is monitored through the changes observed in the I-V curves before and after the specified reaction step. The theoretical results based on the Nernst-Planck and Poisson equations further demonstrate the validity of an experimental approach to fluoride-induced modulation of nanopore current rectification behaviour.

  7. Nanoporous carbon for electrochemical capacitors.

    Energy Technology Data Exchange (ETDEWEB)

    Siegal, Michael P.; Bunker, Bruce Conrad; Limmer, Steven J.; Yelton, William Graham

    2010-05-01

    Nanoporous carbon (NPC) is a purely graphitic material with highly controlled densities ranging from less than 0.1 to 2.0 g/cm3, grown via pulsed-laser deposition. Decreasing the density of NPC increases the interplanar spacing between graphene-sheet fragments. This ability to tune the interplanar spacing makes NPC an ideal model system to study the behavior of carbon electrodes in electrochemical capacitors and batteries. We examine the capacitance of NPC films in alkaline and acidic electrolytes, and measure specific capacitances as high as 242 F/g.

  8. Nanoporous carbon for electrochemical capacitors.

    Energy Technology Data Exchange (ETDEWEB)

    Overmyer, Donald L.; Siegal, Michael P.; Bunker, Bruce Conrad; Limmer, Steven J.; Yelton, William Graham

    2010-04-01

    Nanoporous carbon (NPC) is a purely graphitic material with highly controlled densities ranging from less than 0.1 to 2.0 g/cm3, grown via pulsed-laser deposition. Decreasing the density of NPC increases the interplanar spacing between graphene-sheet fragments. This ability to tune the interplanar spacing makes NPC an ideal model system to study the behavior of carbon electrodes in electrochemical capacitors and batteries. We examine the capacitance of NPC films in alkaline and acidic electrolytes, and measure specific capacitances as high as 242 F/g.

  9. The fabrication of highly ordered block copolymer micellar arrays: control of the separation distances of silicon oxide dots

    Science.gov (United States)

    Yoo, Hana; Park, Soojin

    2010-06-01

    We demonstrate the fabrication of highly ordered silicon oxide dotted arrays prepared from polydimethylsiloxane (PDMS) filled nanoporous block copolymer (BCP) films and the preparation of nanoporous, flexible Teflon or polyimide films. Polystyrene-block-poly(2-vinylpyridine) (PS-b-P2VP) films were annealed in toluene vapor to enhance the lateral order of micellar arrays and were subsequently immersed in alcohol to produce nano-sized pores, which can be used as templates for filling a thin layer of PDMS. When a thin layer of PDMS was spin-coated onto nanoporous BCP films and thermally annealed at a certain temperature, the PDMS was drawn into the pores by capillary action. PDMS filled BCP templates were exposed to oxygen plasma environments in order to fabricate silicon oxide dotted arrays. By addition of PS homopolymer to PS-b-P2VP copolymer, the separation distances of micellar arrays were tuned. As-prepared silicon oxide dotted arrays were used as a hard master for fabricating nanoporous Teflon or polyimide films by spin-coating polymer precursor solutions onto silicon patterns and peeling off. This simple process enables us to fabricate highly ordered nanoporous BCP templates, silicon oxide dots, and flexible nanoporous polymer patterns with feature size of sub-20 nm over 5 cm × 5 cm.

  10. The fabrication of highly ordered block copolymer micellar arrays: control of the separation distances of silicon oxide dots

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Hana; Park, Soojin, E-mail: spark@unist.ac.kr [Interdisciplinary School of Green Energy, Ulsan National Institute of Science and Technology, Banyeon-ri 100, Ulsan 689-798 (Korea, Republic of)

    2010-06-18

    We demonstrate the fabrication of highly ordered silicon oxide dotted arrays prepared from polydimethylsiloxane (PDMS) filled nanoporous block copolymer (BCP) films and the preparation of nanoporous, flexible Teflon or polyimide films. Polystyrene-block-poly(2-vinylpyridine) (PS-b-P2VP) films were annealed in toluene vapor to enhance the lateral order of micellar arrays and were subsequently immersed in alcohol to produce nano-sized pores, which can be used as templates for filling a thin layer of PDMS. When a thin layer of PDMS was spin-coated onto nanoporous BCP films and thermally annealed at a certain temperature, the PDMS was drawn into the pores by capillary action. PDMS filled BCP templates were exposed to oxygen plasma environments in order to fabricate silicon oxide dotted arrays. By addition of PS homopolymer to PS-b-P2VP copolymer, the separation distances of micellar arrays were tuned. As-prepared silicon oxide dotted arrays were used as a hard master for fabricating nanoporous Teflon or polyimide films by spin-coating polymer precursor solutions onto silicon patterns and peeling off. This simple process enables us to fabricate highly ordered nanoporous BCP templates, silicon oxide dots, and flexible nanoporous polymer patterns with feature size of sub-20 nm over 5 cm x 5 cm.

  11. Polarization-induced local pore-wall functionalization for biosensing: from micropore to nanopore.

    Science.gov (United States)

    Liu, Jie; Pham, Pascale; Haguet, Vincent; Sauter-Starace, Fabien; Leroy, Loïc; Roget, André; Descamps, Emeline; Bouchet, Aurélie; Buhot, Arnaud; Mailley, Pascal; Livache, Thierry

    2012-04-03

    The use of biological-probe-modified solid-state pores in biosensing is currently hindered by difficulties in pore-wall functionalization. The surface to be functionalized is small and difficult to target and is usually chemically similar to the bulk membrane. Herein, we demonstrate the contactless electrofunctionalization (CLEF) approach and its mechanism. This technique enables the one-step local functionalization of the single pore wall fabricated in a silica-covered silicon membrane. CLEF is induced by polarization of the pore membrane in an electric field and requires a sandwich-like composition and a conducting or semiconducting core for the pore membrane. The defects in the silica layer of the micropore wall enable the creation of an electric pathway through the silica layer, which allows electrochemical reactions to take place locally on the pore wall. The pore diameter is not a limiting factor for local wall modification using CLEF. Nanopores with a diameter of 200 nm fabricated in a silicon membrane and covered with native silica layer have been successfully functionalized with this method, and localized pore-wall modification was obtained. Furthermore, through proof-of-concept experiments using ODN-modified nanopores, we show that functionalized nanopores are suitable for translocation-based biosensing.

  12. Brownian dynamics simulation of a polymer chain in a solid-state nanopore attached to a molecular stop

    Science.gov (United States)

    Wells, Craig; Hulings, Zachery; Melnikov, Dmitriy; Gracheva, Maria

    We study a nanopore inside a silicon dioxide membrane submerged in a KCl solution with a negatively charged polymer chain of varying lengths whose movement is described using Brownian dynamics. The polymer is attached to a molecule with a radius larger than that of the nanopore's which acts as a molecular stop, allowing the chain to thread the nanopore but preventing it from translocating. We found that the polymer chain's variation of movement along the nanopore decreased when increasing applied biases and chain lengths for portions of the chain closest to the molecular stop. The chain displacement within the pore is also compared to a freely translocating polymer where preliminary results show the free polymer having a greater variation in the radial direction. Overall, our preliminary results indicate that the radial direction of the polymer chain is dominated by the confinement in the narrow nanopore with restrictions imposed by the molecular stop and bias playing a lesser role. Understanding the interaction behavior of the polymer chain-stop molecule may lead to methods that decrease movement variation, facilitating an improvement on characterizing and identification of molecules. NSF DMR and CBET Grant No. 1352218.

  13. Effective antireflection properties of porous silicon nanowires for photovoltaic applications

    KAUST Repository

    Najar, Adel; Al-Jabr, Ahmad; Alsunaidi, Mohammad; Anjum, Dalaver H.; Ng, Tien Khee; Ooi, Boon S.; Ben Slimane, Ahmed; Sougrat, Rachid

    2013-01-01

    Porous silicon nanowires (PSiNWs) have been prepared by metal-assisted chemical etching method on the n-Si substrate. The presence of nano-pores with pore size ranging between 10-50nm in SiNWs was confirmed by electron tomography (ET

  14. Adiabatic burst evaporation from bicontinuous nanoporous membranes

    Science.gov (United States)

    Ichilmann, Sachar; Rücker, Kerstin; Haase, Markus; Enke, Dirk

    2015-01-01

    Evaporation of volatile liquids from nanoporous media with bicontinuous morphology and pore diameters of a few 10 nm is an ubiquitous process. For example, such drying processes occur during syntheses of nanoporous materials by sol–gel chemistry or by spinodal decomposition in the presence of solvents as well as during solution impregnation of nanoporous hosts with functional guests. It is commonly assumed that drying is endothermic and driven by non-equilibrium partial pressures of the evaporating species in the gas phase. We show that nearly half of the liquid evaporates in an adiabatic mode involving burst-like liquid-to-gas conversions. During single adiabatic burst evaporation events liquid volumes of up to 107 μm3 are converted to gas. The adiabatic liquid-to-gas conversions occur if air invasion fronts get unstable because of the built-up of high capillary pressures. Adiabatic evaporation bursts propagate avalanche-like through the nanopore systems until the air invasion fronts have reached new stable configurations. Adiabatic cavitation bursts thus compete with Haines jumps involving air invasion front relaxation by local liquid flow without enhanced mass transport out of the nanoporous medium and prevail if the mean pore diameter is in the range of a few 10 nm. The results reported here may help optimize membrane preparation via solvent-based approaches, solution-loading of nanopore systems with guest materials as well as routine use of nanoporous membranes with bicontinuous morphology and may contribute to better understanding of adsorption/desorption processes in nanoporous media. PMID:25926406

  15. Highly efficient human serum filtration with water-soluble nanoporous nanoparticles

    Directory of Open Access Journals (Sweden)

    Antonella Pujia

    2010-11-01

    Full Text Available Antonella Pujia1, Francesco De Angelis1,2, Domenica Scumaci3, Marco Gaspari3, Carlo Liberale1,2, Patrizio Candeloro1, Giovanni Cuda3, Enzo Di Fabrizio1,21BIONEM Laboratory, Department of Experimental and Clinical Medicine, University of Catanzaro “Magna Graecia”, Germaneto (CZ, Italy; 2IIT, Italian Institute of Technology, Genova, Italy; 3Proteomics and Mass Spectrometry Laboratory, Department of Experimental and Clinical Medicine, University of Catanzaro “Magna Graecia”, Germaneto (CZ, ItalyBackground: Human serum has the potential to become the most informative source of novel biomarkers, but its study is very difficult due to the incredible complexity of its molecular composition. We describe a novel tool based on biodegradable nanoporous nanoparticles (NPNPs that allows the harvesting of low-molecular-weight fractions of crude human serum or other biofluids. NPNPs with a diameter of 200 nm and pore size of a few nm were obtained by ultrasonication of nanoporous silicon. When incubated with a solution, the NPNPs harvest only the molecules small enough to be absorbed into the nanopores. Then they can be recovered by centrifugation and dissolved in water, making the harvested molecules available for further analyses.Results: Fluorescence microscopy, gel electrophoresis, and mass spectrometry were used to show the enrichment of low-molecular-weight fraction of serum under physiological conditions, with a cut-off of 13 kDa and an enrichment factor >50.Conclusion: From these findings, we conclude that ability to tune pore size, combined with the availability of hundreds of biomolecule cross-linkers, opens up new perspectives on complex biofluid analysis, discovery of biomarkers, and in situ drug delivery.Keywords: nanoporous silicon, nanoparticle, biomarker discovery, human serum proteomics, harvesting

  16. Nanopore biosensors for detection of proteins and nucleic acids

    NARCIS (Netherlands)

    Maglia, Giovanni; Soskine, Mikhael

    2014-01-01

    Described herein are nanopore biosensors based on a modified cytolysin protein. The nanopore biosensors accommodate macromoiecules including proteins and nucleic acids, and may additionally comprise ligands with selective binding properties.

  17. Thermal carbonization of nanoporous silicon: Formation of carbon ...

    Indian Academy of Sciences (India)

    Raman, Fourier transform infrared spectroscopy (FTIR) and electron microscope studies, revealed that the ... the carbonization of PS, the argon gas flow rate was kept at 30 sccm. In the mean time, ... ion laser (Spectra Physics) tuned at 488 nm.

  18. Silicone metalization

    Energy Technology Data Exchange (ETDEWEB)

    Maghribi, Mariam N. (Livermore, CA); Krulevitch, Peter (Pleasanton, CA); Hamilton, Julie (Tracy, CA)

    2008-12-09

    A system for providing metal features on silicone comprising providing a silicone layer on a matrix and providing a metal layer on the silicone layer. An electronic apparatus can be produced by the system. The electronic apparatus comprises a silicone body and metal features on the silicone body that provide an electronic device.

  19. ELECTROCHEMICAL PROPERTIES OF NANOPOROUS CARBON ELECTRODES

    Directory of Open Access Journals (Sweden)

    P.Nigu

    2002-01-01

    Full Text Available Electrical double layer and electrochemical characteristics at the nanoporous carbon | (C2H54NBF4 + acetonitrile interface have been studied by the cyclic voltammetry and impedance spectroscopy methods. The value of zero charge potential (0.23 V vs. SCE in H2O, the region of ideal polarizability and other characteristics have been established. Analysis of complex plane plots shows that the nanoporous carbon | x M (C2H54NBF4 + acetonitrile interface can be simulated by the equivalent circuit, in which the two parallel conduction parts in the solid and liquid phases are interconnected by the double layer capacitance in parallel with the complex admittance of hindered reaction of the charge transfer process. The values of the characteristic frequency depend on the electrolyte concentration and on the electrode potential, i.e. on the nature of ions adsorbed at the surface of nanoporous carbon electrode.

  20. Dynamic crack propagation through nanoporous media

    Science.gov (United States)

    Nguyen, Thao; Wilkerson, Justin

    2015-06-01

    The deformation and failure of nanoporous metals may be considerably different than that of more traditional bulk porous metals. The length scales in traditional bulk porous metals are typically large enough for classic plasticity and buckling to be operative. However, the extremely small length scales associated with nanoporous metals may inhibit classic plasticity mechanisms. Here, we motivate an alternative nanovoid growth mechanism mediated by dislocation emission. Following an approach similar to Lubarda and co-workers, we make use of stability arguments applied to the analytic solutions of the elastic interactions of dislocations and voids to derive a simple stress-based criterion for emission activation. We then propose a dynamic nanovoid growth law that is motivated by the kinetics of dislocation emission. The resulting failure model is implemented into a commercial finite element software to simulate dynamic crack growth. The simulations reveal that crack propagation through a nanoporous media proceeds at somewhat faster velocities than through the more traditional bulk porous metal.

  1. Brownian dynamics of a protein-polymer chain complex in a solid-state nanopore

    Science.gov (United States)

    Wells, Craig C.; Melnikov, Dmitriy V.; Gracheva, Maria E.

    2017-08-01

    We study the movement of a polymer attached to a large protein inside a nanopore in a thin silicon dioxide membrane submerged in an electrolyte solution. We use Brownian dynamics to describe the motion of a negatively charged polymer chain of varying lengths attached to a neutral protein modeled as a spherical bead with a radius larger than that of the nanopore, allowing the chain to thread the nanopore but preventing it from translocating. The motion of the protein-polymer complex within the pore is also compared to that of a freely translocating polymer. Our results show that the free polymer's standard deviations in the direction normal to the pore axis is greater than that of the protein-polymer complex. We find that restrictions imposed by the protein, bias, and neighboring chain segments aid in controlling the position of the chain in the pore. Understanding the behavior of the protein-polymer chain complex may lead to methods that improve molecule identification by increasing the resolution of ionic current measurements.

  2. Synthesis and characterization of ruthenium-decorated nanoporous platinum materials

    International Nuclear Information System (INIS)

    Peng Xinsheng; Koczkur, Kallum; Chen, Aicheng

    2007-01-01

    We report on the synthesis of novel three-dimensional nanoporous Pt-Ru bimetallic networks by decorating nanoporous Pt networks with Ru using a hydrothermally assisted precipitating process. Scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDS) were used to characterize the morphology and the composition of the nanoporous Pt-Ru networks formed. X-ray diffraction analysis confirmed that, after protected annealing treatment, Pt-Ru bimetallic material was formed. The electrocatalytic activity of the synthesized nanoporous Pt-Ru networks was characterized using electrochemical oxidation of methanol as a probe. The electrocatalytic activity of the nanoporous Pt networks significantly increases with the increments of decorated Ru and reaches the highest value with 41% of Ru. The peak current of methanol oxidation on the nanoporous Pt-Ru(41%) bimetallic networks is over 180% higher than that on the nanoporous Pt networks without Ru decoration. This is very desirable for fuel cell development and electrochemical sensor design

  3. Expanding the functionality and applications of nanopore sensors

    Science.gov (United States)

    Venta, Kimberly E.

    Nanopore sensors have developed into powerful tools for single-molecule studies since their inception two decades ago. Nanopore sensors function as nanoscale Coulter counters, by monitoring ionic current modulations as particles pass through a nanopore. While nanopore sensors can be used to study any nanoscale particle, their most notable application is as a low cost, fast alternative to current DNA sequencing technologies. In recent years, signifcant progress has been made toward the goal of nanopore-based DNA sequencing, which requires an ambitious combination of a low-noise and high-bandwidth nanopore measurement system and spatial resolution. In this dissertation, nanopore sensors in thin membranes are developed to improve dimensional resolution, and these membranes are used in parallel with a high-bandwidth amplfier. Using this nanopore sensor system, the signals of three DNA homopolymers are differentiated for the first time in solid-state nanopores. The nanopore noise is also reduced through the addition of a layer of SU8, a spin-on polymer, to the supporting chip structure. By increasing the temporal and spatial resolution of nanopore sensors, studies of shorter molecules are now possible. Nanopore sensors are beginning to be used for the study and characterization of nanoparticles. Nanoparticles have found many uses from biomedical imaging to next-generation solar cells. However, further insights into the formation and characterization of nanoparticles would aid in developing improved synthesis methods leading to more effective and customizable nanoparticles. This dissertation presents two methods of employing nanopore sensors to benet nanoparticle characterization and fabrication. Nanopores were used to study the formation of individual nanoparticles and serve as nanoparticle growth templates that could be exploited to create custom nanoparticle arrays. Additionally, nanopore sensors were used to characterize the surface charge density of anisotropic

  4. Mechanisms of material removal and mass transport in focused ion beam nanopore formation

    Energy Technology Data Exchange (ETDEWEB)

    Das, Kallol, E-mail: das7@illinois.edu; Johnson, Harley T., E-mail: htj@illinois.edu [Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, 1206 West Green Street, MC-244, Urbana, Illinois 61801 (United States); Freund, Jonathan B., E-mail: jbfreund@illinois.edu [Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, 1206 West Green Street, MC-244, Urbana, Illinois 61801 (United States); Department of Aerospace Engineering, University of Illinois at Urbana-Champaign, 306 Talbot Laboratory, MC-236, 104 South Wright Street Urbana, Illinois 61801 (United States)

    2015-02-28

    Despite the widespread use of focused ion beam (FIB) processing as a material removal method for applications ranging from electron microscope sample preparation to nanopore processing for DNA sequencing, the basic material removal mechanisms of FIB processing are not well understood. We present the first complete atomistic simulation of high-flux FIB using large-scale parallel molecular dynamics (MD) simulations of nanopore fabrication in freestanding thin films. We focus on the root mechanisms of material removal and rearrangement and describe the role of explosive boiling in forming nanopores. FIB nanopore fabrication is typically understood to occur via sputter erosion. This can be shown to be the case in low flux systems, where individual ion impacts are sufficiently separated in time that they may be considered as independent events. But our detailed MD simulations show that in high flux FIB processing, above a threshold level at which thermal effects become significant, the primary mechanism of material removal changes to a significantly accelerated, thermally dominated process. Under these conditions, the target is heated by the ion beam faster than heat is conducted away by the material, leading quickly to melting, and then continued heating to nearly the material critical temperature. This leads to explosive boiling of the target material with spontaneous bubble formation and coalescence. Mass is rapidly rearranged at the atomistic scale, and material removal occurs orders of magnitude faster than would occur by simple sputtering. While the phenomenology is demonstrated computationally in silicon, it can be expected to occur at lower beam fluxes in other cases where thermal conduction is suppressed due to material properties, geometry, or ambient thermal conditions.

  5. Nanopore formation on Au coated pyramid under electron beam irradiations (plasmonic nanopore on pyramid

    Directory of Open Access Journals (Sweden)

    Seong Soo Choi

    2016-03-01

    Full Text Available There have been tremendous interests about the single molecule analysis using a sold-state nanopore. The solid-state nanopore can be fabricated either by drilling technique, or diffusion technique by using electron beam irradiations. The solid-state SiN nanopore device with electrical detection technique recently fabricated, however, the solid-state Au nanopore with optical detection technique can be better utilized as the next generation single molecule sensor. In this report, the nanometer size openings with its size less than 10 nm on the diffused membrane on the 200 nm Au pyramid were fabricated by using field emission scanning electron microscopy (FESEM electron beam irradiations, transmission electron microscopy (TEM, etc. After the sample was being kept under a room environment for several months, several Au (111 clusters with ~6 nm diameter formed via Ostwald ripening are observed using a high resolution TEM imaging. The nanopore with Au nanoclusters on the diffused membrane can be utilized as an optical nanopore device. Keywords: Electron beam irradiation, Surface diffusion, Carbon contamination, Au cluster, Ostwald ripening

  6. Secondary electron emission in nanostructured porous silicon

    Energy Technology Data Exchange (ETDEWEB)

    Ruano, G D; Ferron, J; Koropecki, R R, E-mail: gdruano@ceride.gov.a [INTEC-UNL-CONICET, Gueemes 3450 - 3000 Santa Fe (Argentina)

    2009-05-01

    We studied the reversible reduction induced by ion bombardment of the secondary electron emission (SEE) yield. This effect has been modelled as due to changes in dynamically sustained dipoles related with ions and electrons penetration ranges. Such charge configuration precludes the escape of electrons from the nanoporous silicon, making the SEE dependent on the flux of impinging ions. Since this dipolar momentum depends on the electric conduction of the porous medium, by controlled oxidation of the nanoporous structure we change the conduction features of the sample, studying the impact on the SEE reduction effect. Li ion bombardment was also used with the intention of changing the parameters determining the effect. FT-IR and Auger electron spectroscopy were used to characterize the oxidation degree of the samples at different depth scales

  7. Nanoporous silica membranes with high hydrothermal stability

    DEFF Research Database (Denmark)

    Boffa, Vittorio; Magnacca, Giualiana; Yue, Yuanzheng

    to improve the stability of nanoporous silica structure. This work is a quantitative study on the impact of type and concentration of transition metal ions on the microporous structure and stability of amorphous silica-based membranes, which provides information on how to design chemical compositions...

  8. Gassmann Theory Applies to Nanoporous Media

    Science.gov (United States)

    Gor, Gennady Y.; Gurevich, Boris

    2018-01-01

    Recent progress in extraction of unconventional hydrocarbon resources has ignited the interest in the studies of nanoporous media. Since many thermodynamic and mechanical properties of nanoscale solids and fluids differ from the analogous bulk materials, it is not obvious whether wave propagation in nanoporous media can be described using the same framework as in macroporous media. Here we test the validity of Gassmann equation using two published sets of ultrasonic measurements for a model nanoporous medium, Vycor glass, saturated with two different fluids, argon, and n-hexane. Predictions of the Gassmann theory depend on the bulk and shear moduli of the dry samples, which are known from ultrasonic measurements and the bulk moduli of the solid and fluid constituents. The solid bulk modulus can be estimated from adsorption-induced deformation or from elastic effective medium theory. The fluid modulus can be calculated according to the Tait-Murnaghan equation at the solvation pressure in the pore. Substitution of these parameters into the Gassmann equation provides predictions consistent with measured data. Our findings set up a theoretical framework for investigation of fluid-saturated nanoporous media using ultrasonic elastic wave propagation.

  9. Optical characterization of nanoporous AAO sensor substrate

    Science.gov (United States)

    Kassu, Aschalew; Farley, Carlton W.; Sharma, Anup

    2014-05-01

    Nanoporous anodic aluminum oxide (AAO) has been investigated as an ideal and cost-effective chemical and biosensing platform. In this paper, we report the optical properties of periodic 100 micron thick nanoporous anodic alumina membranes with uniform and high density cylindrical pores penetrating the entire thickness of the substrate, ranging in size from 18 nm to 150 nm in diameter and pore periods from 44 nm to 243 nm. The surface geometry of the top and bottom surface of each membrane is studied using atomic force microscopy. The optical properties including transmittance, reflectance, and absorbance spectra on both sides of each substrate are studied and found to be symmetrical. It is observed that, as the pore size increases, the peak resonance intensity in transmittance decreases and in absorbance increases. The effects of the pore sizes on the optical properties of the bare nanoporous membranes and the benefit of using arrays of nanohole arrays with varying hole size and periodicity as a chemical sensing platform is also discussed. To characterize the optical sensing technique, transmittance and reflectance measurements of various concentrations of a standard chemical adsorbed on the bare nanoporous substrates are investigated. The preliminary results presented here show variation in transmittance and reflectance spectra with the concentration of the chemical used or the amount of the material adsorbed on the surface of the substrate.

  10. Transparent Nanopore Cavity Arrays Enable Highly Parallelized Optical Studies of Single Membrane Proteins on Chip.

    Science.gov (United States)

    Diederichs, Tim; Nguyen, Quoc Hung; Urban, Michael; Tampé, Robert; Tornow, Marc

    2018-06-13

    Membrane proteins involved in transport processes are key targets for pharmaceutical research and industry. Despite continuous improvements and new developments in the field of electrical readouts for the analysis of transport kinetics, a well-suited methodology for high-throughput characterization of single transporters with nonionic substrates and slow turnover rates is still lacking. Here, we report on a novel architecture of silicon chips with embedded nanopore microcavities, based on a silicon-on-insulator technology for high-throughput optical readouts. Arrays containing more than 14 000 inverted-pyramidal cavities of 50 femtoliter volumes and 80 nm circular pore openings were constructed via high-resolution electron-beam lithography in combination with reactive ion etching and anisotropic wet etching. These cavities feature both, an optically transparent bottom and top cap. Atomic force microscopy analysis reveals an overall extremely smooth chip surface, particularly in the vicinity of the nanopores, which exhibits well-defined edges. Our unprecedented transparent chip design provides parallel and independent fluorescent readout of both cavities and buffer reservoir for unbiased single-transporter recordings. Spreading of large unilamellar vesicles with efficiencies up to 96% created nanopore-supported lipid bilayers, which are stable for more than 1 day. A high lipid mobility in the supported membrane was determined by fluorescent recovery after photobleaching. Flux kinetics of α-hemolysin were characterized at single-pore resolution with a rate constant of 0.96 ± 0.06 × 10 -3 s -1 . Here, we deliver an ideal chip platform for pharmaceutical research, which features high parallelism and throughput, synergistically combined with single-transporter resolution.

  11. Recent advances in nanopore-based nucleic acid analysis and sequencing

    International Nuclear Information System (INIS)

    Shi, Jidong; Fang, Ying; Hou, Junfeng

    2016-01-01

    Nanopore-based sequencing platforms are transforming the field of genomic science. This review (containing 116 references) highlights some recent progress on nanopore-based nucleic acid analysis and sequencing. These studies are classified into three categories, biological, solid-state, and hybrid nanopores, according to their nanoporous materials. We begin with a brief description of the translocation-based detection mechanism of nanopores. Next, specific examples are given in nanopore-based nucleic acid analysis and sequencing, with an emphasis on identifying strategies that can improve the resolution of nanopores. This review concludes with a discussion of future research directions that will advance the practical applications of nanopore technology. (author)

  12. Recent Advances in Nanoporous Membranes for Water Purification

    Directory of Open Access Journals (Sweden)

    Zhuqing Wang

    2018-01-01

    Full Text Available Nanoporous materials exhibit wide applications in the fields of electrocatalysis, nanodevice fabrication, energy, and environmental science, as well as analytical science. In this review, we present a summary of recent studies on nanoporous membranes for water purification application. The types and fabrication strategies of various nanoporous membranes are first introduced, and then the fabricated nanoporous membranes for removing various water pollutants, such as salt, metallic ions, anions, nanoparticles, organic chemicals, and biological substrates, are demonstrated and discussed. This work will be valuable for readers to understand the design and fabrication of various nanoporous membranes, and their potential purification mechanisms towards different water pollutants. In addition, it will be helpful for developing new nanoporous materials for quick, economic, and high-performance water purification.

  13. Study of polymer molecules and conformations with a nanopore

    Science.gov (United States)

    Golovchenko, Jene A.; Li, Jiali; Stein, Derek; Gershow, Marc H.

    2010-12-07

    The invention features methods for evaluating the conformation of a polymer, for example, for determining the conformational distribution of a plurality of polymers and to detect binding or denaturation events. The methods employ a nanopore which the polymer, e.g., a nucleic acid, traverses. As the polymer traverses the nanopore, measurements of transport properties of the nanopore yield data on the conformation of the polymer.

  14. Energy absorption behaviors of nanoporous materials functionalized (NMF) liquids

    OpenAIRE

    Kim, Tae Wan

    2011-01-01

    For many decades, people have been actively investigating high-performance energy absorption materials, so as to develop lightweight and small-sized protective and damping devices, such as blast mitigation helmets, vehicle armors, etc. Recently, the high energy absorption efficiency of nanoporous materials functionalized (NMF) liquids has drawn considerable attention. A NMF liquid is usually a liquid suspension of nanoporous particles with large nanopore surface areas (100 - 2,000 m²/g). The ...

  15. Nanoporous Polymeric Grating-Based Optical Biosensors (Preprint)

    National Research Council Canada - National Science Library

    Hsiao, Vincent K; Waldeisen, John R; Lloyd, Pamela F; Bunning, Timothy J; Huang, Tony J

    2007-01-01

    .... The fabrication process of the nanoporous polymeric grating involves holographic interference patterning and a functionalized pre-polymer syrup that facilitates the immobilization of biomolecules...

  16. Nanoporous Cyclic Brush Polymers for Selective Carbon Dioxide Capture

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective of the proposed work is to develop advanced synthetic methodologies that afford nanoporous materials with selective uptake affinity towards carbon...

  17. Nanoporous Membrane Technologies for Pathogen Collection, Separation, and Detection

    National Research Council Canada - National Science Library

    Lee, Sang W; Shang, Hao; Lee, Gil U; Griffin, Matthew T; Fulton, Jack

    2003-01-01

    Partial contents: Nanoporous Membranes, Membrane Chemistries, Characterization of Membrane Chemistries,Protein Fouling, Collector,Gas and Liquid Permeabilities, Membrane Permeabilities in the Presence of Water...

  18. Silicon detectors

    International Nuclear Information System (INIS)

    Klanner, R.

    1984-08-01

    The status and recent progress of silicon detectors for high energy physics is reviewed. Emphasis is put on detectors with high spatial resolution and the use of silicon detectors in calorimeters. (orig.)

  19. Ordered arrays of nanoporous gold nanoparticles

    Directory of Open Access Journals (Sweden)

    Dong Wang

    2012-09-01

    Full Text Available A combination of a “top-down” approach (substrate-conformal imprint lithography and two “bottom-up” approaches (dewetting and dealloying enables fabrication of perfectly ordered 2-dimensional arrays of nanoporous gold nanoparticles. The dewetting of Au/Ag bilayers on the periodically prepatterned substrates leads to the interdiffusion of Au and Ag and the formation of an array of Au–Ag alloy nanoparticles. The array of alloy nanoparticles is transformed into an array of nanoporous gold nanoparticles by a following dealloying step. Large areas of this new type of material arrangement can be realized with this technique. In addition, this technique allows for the control of particle size, particle spacing, and ligament size (or pore size by varying the period of the structure, total metal layer thickness, and the thickness ratio of the as-deposited bilayers.

  20. Force fluctuations assist nanopore unzipping of DNA

    International Nuclear Information System (INIS)

    Viasnoff, V; Chiaruttini, N; Muzard, J; Bockelmann, U

    2010-01-01

    We experimentally study the statistical distributions and the voltage dependence of the unzipping time of 45 base-pair-long double-stranded DNA through a nanopore. We then propose a quantitative theoretical description considering the nanopore unzipping process as a random walk of the opening fork through the DNA sequence energy landscape biased by a time-fluctuating force. To achieve quantitative agreement fluctuations need to be correlated over the millisecond range and have an amplitude of order k B T/bp. Significantly slower or faster fluctuations are not appropriate, suggesting that the unzipping process is efficiently enhanced by noise in the kHz range. We further show that the unzipping time of short 15 base-pair hairpins does not always increase with the global stability of the double helix and we theoretically study the role of DNA elasticity on the conversion of the electrical bias into a mechanical unzipping force.

  1. Thermodynamics phase changes of nanopore fluids

    KAUST Repository

    Islam, Akand W.; Patzek, Tadeusz; Sun, Alexander Y.

    2015-01-01

    The van der Waals (vdW) equation (Eq.) is modified to describe thermodynamic of phase behavior of fluids confined in nanopore. Our aim is to compute pressures exerted by the fluid molecules and to investigate how they change due to pore proximity by assuming the pore wall is inert. No additional scaling of model parameters is imposed and original volume and energy parameters are used in the calculations. Our results clearly show the phase changes due to confinement. The critical shifts of temperatures and pressures are in good agreement compared to the laboratory data and molecular simulation. Peng-Robinson (PR) equation-of-state (EOS) has resulted in different effect than the vdW. This work delivers insights into the nature of fluid behavior in extremely low-permeability nanoporous media, especially in the tight shale reservoirs, below the critical temperatures. © 2015 Elsevier B.V.

  2. Thermodynamics phase changes of nanopore fluids

    KAUST Repository

    Islam, Akand W.

    2015-07-01

    The van der Waals (vdW) equation (Eq.) is modified to describe thermodynamic of phase behavior of fluids confined in nanopore. Our aim is to compute pressures exerted by the fluid molecules and to investigate how they change due to pore proximity by assuming the pore wall is inert. No additional scaling of model parameters is imposed and original volume and energy parameters are used in the calculations. Our results clearly show the phase changes due to confinement. The critical shifts of temperatures and pressures are in good agreement compared to the laboratory data and molecular simulation. Peng-Robinson (PR) equation-of-state (EOS) has resulted in different effect than the vdW. This work delivers insights into the nature of fluid behavior in extremely low-permeability nanoporous media, especially in the tight shale reservoirs, below the critical temperatures. © 2015 Elsevier B.V.

  3. Functional Nanoporous Polymers from Block Copolymer Precursors

    DEFF Research Database (Denmark)

    Guo, Fengxiao

    Abstract Self-assembly of block copolymers provides well-defined morphologies with characteristic length scales in the nanometer range. Nanoporous polymers prepared by selective removal of one block from self-assembled block copolymers offer great technological promise due to their many potential...... functionalities remains a great challenge due to the limitation of available polymer synthesis and the nanoscale confinement of the porous cavities. The main topic of this thesis is to develop methods for fabrication of functional nanoporous polymers from block copolymer precursors. A method has been developed......, where living anionic polymerization and atom transfer radical polymerization (ATRP) are combined to synthesize a polydimethylsiloxane-b-poly(tert-butyl acrylate)-b-polystyrene (PDMS-b-PtBA-b-PS) triblock copolymer precursor. By using either anhydrous hydrogen fluoride or trifluoroacetic acid, PtBA block...

  4. Nanoporous hard data: optical encoding of information within nanoporous anodic alumina photonic crystals.

    Science.gov (United States)

    Santos, Abel; Law, Cheryl Suwen; Pereira, Taj; Losic, Dusan

    2016-04-21

    Herein, we present a method for storing binary data within the spectral signature of nanoporous anodic alumina photonic crystals. A rationally designed multi-sinusoidal anodisation approach makes it possible to engineer the photonic stop band of nanoporous anodic alumina with precision. As a result, the transmission spectrum of these photonic nanostructures can be engineered to feature well-resolved and selectively positioned characteristic peaks across the UV-visible spectrum. Using this property, we implement an 8-bit binary code and assess the versatility and capability of this system by a series of experiments aiming to encode different information within the nanoporous anodic alumina photonic crystals. The obtained results reveal that the proposed nanosized platform is robust, chemically stable, versatile and has a set of unique properties for data storage, opening new opportunities for developing advanced nanophotonic tools for a wide range of applications, including sensing, photonic tagging, self-reporting drug releasing systems and secure encoding of information.

  5. Understanding Energy Absorption Behaviors of Nanoporous Materials

    Science.gov (United States)

    2008-05-23

    induced liquid infiltration in nanopores. J. Appl. Phys. 100, 014308.1-3 (2006). 26. Surani, F. B. and Qiao, Y. Energy absorption of a polyacrylic ...that the infiltration pressure decreases as the cation size increases (Fig.K-2). The ionic radii of cesium, potassium , sodium and lithium are...REPORT DOCUMENTATION PAGE Form Approved OMB NO. 0704-0188 Public Reporting burden for this collection of information is estimated to average 1 hour

  6. Broadband Spectroscopy of Nanoporous-Gold Promoter

    Directory of Open Access Journals (Sweden)

    S. K. Nakatani

    2014-02-01

    Full Text Available The efficiency of UV photocatalysis on TiO2 particles was increased by mixing TiO2 particles with nanoporous gold (NPG with pore diameters of 10–40 nm. This means that NPG acts as a promoter in the photocatalytic reaction of TiO2. Broadband spectroscopic results from millimeter wave to ultra violet of NPG membrane are discussed to estimate plasmonic effect on the catalysis.

  7. Controlling Ionic Transport for Device Design in Synthetic Nanopores

    Science.gov (United States)

    Kalman, Eric Boyd

    Polymer nanopores present a number of behaviors not seen in microscale systems, such as ion current rectification, ionic selectivity, size exclusion and potential dependent ion concentrations in and near the pore. The existence of these effects stems from the small size of nanopores with respect to the characteristic length scales of surface interactions at the interface between the nanopore surface and the solution within it. The large surface-to-volume ratio due to the nanoscale geometry of a nanopore, as well as similarity in scale between geometry and interaction demands the solution interact with the nanopore walls. As surfaces in solution almost always carry residual charge, these surface forces are primarily the electrostatic interactions between the charge groups on the pore surface and the ions in solution. These interactions may be used by the experimentalist to control ionic transport through synthetic nanopores, and use them as a template for the construction of devices. In this research, we present our work on creating a number of ionic analogs to seminal electronic devices, specifically diodes, and transistors, by controlling ionic transport through the electrostatic interactions between a single synthetic nanopore and ions. Control is achieved by "doping" the effective charge carrier concentration in specific regions of the nanopore through manipulation of the pore's surface charge. This manipulation occurs through two mechanisms: chemical modification of the surface charge and electrostatic manipulation of the local internal nanopore potential using a gate electrode. Additionally, the innate selectivity of the charged nanopores walls allows for the separation of charges in solution. This well-known effect, which spawns measureable quantities, the streaming potential and current, has been used to create nanoscale water desalination membranes. We attempt to create a device using membranes with large nanopore densities for the desalination of water

  8. Tuneable graphene nanopores for single biomolecule detection.

    Science.gov (United States)

    Al-Dirini, Feras; Mohammed, Mahmood A; Hossain, Md Sharafat; Hossain, Faruque M; Nirmalathas, Ampalavanapillai; Skafidas, Efstratios

    2016-05-21

    Solid-state nanopores are promising candidates for next generation DNA and protein sequencing. However, once fabricated, such devices lack tuneability, which greatly restricts their biosensing capabilities. Here we propose a new class of solid-state graphene-based nanopore devices that exhibit a unique capability of self-tuneability, which is used to control their conductance, tuning it to levels comparable to the changes caused by the translocation of a single biomolecule, and hence, enabling high detection sensitivities. Our presented quantum simulation results suggest that the smallest amino acid, glycine, when present in water and in an aqueous saline solution can be detected with high sensitivity, up to a 90% change in conductance. Our results also suggest that passivating the device with nitrogen, making it an n-type device, greatly enhances its sensitivity, and makes it highly sensitive to not only the translocation of a single biomolecule, but more interestingly to intramolecular electrostatics within the biomolecule. Sensitive detection of the carboxyl group within the glycine molecule, which carries a charge equivalent to a single electron, is achieved with a conductance change that reaches as high as 99% when present in an aqueous saline solution. The presented findings suggest that tuneable graphene nanopores, with their capability of probing intramolecular electrostatics, could pave the way towards a new generation of single biomolecule detection devices.

  9. Characterization of nanoporous shales with gas sorption

    Science.gov (United States)

    Joewondo, N.; Prasad, M.

    2017-12-01

    The understanding of the fluid flow in porous media requires the knowledge of the pore system involved. Fluid flow in fine grained shales falls under different regime than transport regime in conventional reservoir due to the different average pore sizes in the two materials; the average pore diameter of conventional sandstones is on the micrometer scale, while of shales can be as small as several nanometers. Mercury intrusion porosimetry is normally used to characterize the pores of conventional reservoir, however with increasingly small pores, the injection pressure required to imbibe the pores becomes infinitely large due to surface tension. Characterization of pores can be expressed by a pore size distribution (PSD) plot, which reflects distribution of pore volume or surface area with respect to pore size. For the case of nanoporous materials, the surface area, which serves as the interface between the rock matrix and fluid, becomes increasingly large and important. Physisorption of gas has been extensively studied as a method of nanoporous solid characterization (particularly for the application of catalysis, metal organic frameworks, etc). The PSD is obtained by matching the experimental result to the calculated theoretical result (using Density Functional Theory (DFT), a quantum mechanics based modelling method for molecular scale interactions). We present the challenges and experimental result of Nitrogen and CO2 gas sorption on shales with various mineralogy and the interpreted PSD obtained by DFT method. Our result shows significant surface area contributed by the nanopores of shales, hence the importance of surface area measurements for the characterization of shales.

  10. Direct laser writing for nanoporous liquid core laser sensors

    DEFF Research Database (Denmark)

    Grossmann, Tobias; Christiansen, Mads Brøkner; Peterson, Jeffrey

    2012-01-01

    We report the fabrication of nanoporous liquid core lasers via direct laser writing based on two-photon absorption in combination with thiolene-chemistry. As gain medium Rhodamine 6G was embedded in the nanoporous polybutadiene matrix. The lasing devices with thresholds of 19 µJ/mm2 were measured...

  11. UV patterned nanoporous solid-liquid core waveguides

    DEFF Research Database (Denmark)

    Gopalakrishnan, Nimi; Sagar, Kaushal Shashikant; Christiansen, Mads Brøkner

    2010-01-01

    Nanoporous Solid-Liquid core waveguides were prepared by UV induced surface modification of hydrophobic nanoporous polymers. With this method, the index contrast (delta n = 0.20) is a result of selective water infiltration. The waveguide core is defined by UV light, rendering the exposed part...

  12. Physisorption of SDS in a Hydrocarbon Nanoporous Polymer

    DEFF Research Database (Denmark)

    Li, Li; Wang, Yanwei; Vigild, Martin Etchells

    2010-01-01

    Surface modification of nanoporous 1,2-polybutadiene of pore diameter similar to 15 nm was accomplished by physisorption of sodium dodecyl sulfate (SDS) in water. Loading of the aqueous solution and the accompanying physisorption of SDS into the hydrophobic nanoporous films were investigated in a...

  13. DNA and ion transport through solid-state nanopores

    NARCIS (Netherlands)

    Smeets, R.M.M.

    2008-01-01

    This thesis describes experimental work on a novel type of devices capable of detecting single-(bio)molecules; nanometer-sized pores, or nanopores. Individual nanopores are placed in between two electrolyte-filled liquid compartments and (bio)molecules are electrophoretically driven through them.

  14. Nanoparticle mechanics: deformation detection via nanopore resistive pulse sensing

    Science.gov (United States)

    Darvish, Armin; Goyal, Gaurav; Aneja, Rachna; Sundaram, Ramalingam V. K.; Lee, Kidan; Ahn, Chi Won; Kim, Ki-Bum; Vlahovska, Petia M.; Kim, Min Jun

    2016-07-01

    Solid-state nanopores have been widely used in the past for single-particle analysis of nanoparticles, liposomes, exosomes and viruses. The shape of soft particles, particularly liposomes with a bilayer membrane, can greatly differ inside the nanopore compared to bulk solution as the electric field inside the nanopores can cause liposome electrodeformation. Such deformations can compromise size measurement and characterization of particles, but are often neglected in nanopore resistive pulse sensing. In this paper, we investigated the deformation of various liposomes inside nanopores. We observed a significant difference in resistive pulse characteristics between soft liposomes and rigid polystyrene nanoparticles especially at higher applied voltages. We used theoretical simulations to demonstrate that the difference can be explained by shape deformation of liposomes as they translocate through the nanopores. Comparing our results with the findings from electrodeformation experiments, we demonstrated that the rigidity of liposomes can be qualitatively compared using resistive pulse characteristics. This application of nanopores can provide new opportunities to study the mechanics at the nanoscale, to investigate properties of great value in fundamental biophysics and cellular mechanobiology, such as virus deformability and fusogenicity, and in applied sciences for designing novel drug/gene delivery systems.Solid-state nanopores have been widely used in the past for single-particle analysis of nanoparticles, liposomes, exosomes and viruses. The shape of soft particles, particularly liposomes with a bilayer membrane, can greatly differ inside the nanopore compared to bulk solution as the electric field inside the nanopores can cause liposome electrodeformation. Such deformations can compromise size measurement and characterization of particles, but are often neglected in nanopore resistive pulse sensing. In this paper, we investigated the deformation of various

  15. Surface effects on the mechanical properties of nanoporous materials

    International Nuclear Information System (INIS)

    Xia Re; Li Xide; Feng Xiqiao; Qin Qinghua; Liu Jianlin

    2011-01-01

    Using the theory of surface elasticity, we investigate the mechanical properties of nanoporous materials. The classical theory of porous materials is modified to account for surface effects, which become increasingly important as the characteristic sizes of microstructures shrink to nanometers. First, a refined Timoshenko beam model is presented to predict the effective elastic modulus of nanoporous materials. Then the surface effects on the elastic microstructural buckling behavior of nanoporous materials are examined. In particular, nanoporous gold is taken as an example to illustrate the application of the proposed model. The results reveal that both the elastic modulus and the critical buckling behavior of nanoporous materials exhibit a distinct dependence on the characteristic sizes of microstructures, e.g. the average ligament width.

  16. Surface effects on the mechanical properties of nanoporous materials

    Energy Technology Data Exchange (ETDEWEB)

    Xia Re [School of Power and Mechanical Engineering, Wuhan University, Wuhan 430072 (China); Li Xide; Feng Xiqiao [AML, Department of Engineering Mechanics, Tsinghua University, Beijing 100084 (China); Qin Qinghua [School of Engineering, Australian National University, Canberra, ACT 0200 (Australia); Liu Jianlin, E-mail: fengxq@tsinghua.edu.cn [Department of Engineering Mechanics, China University of Petroleum, Qingdao 266555 (China)

    2011-07-01

    Using the theory of surface elasticity, we investigate the mechanical properties of nanoporous materials. The classical theory of porous materials is modified to account for surface effects, which become increasingly important as the characteristic sizes of microstructures shrink to nanometers. First, a refined Timoshenko beam model is presented to predict the effective elastic modulus of nanoporous materials. Then the surface effects on the elastic microstructural buckling behavior of nanoporous materials are examined. In particular, nanoporous gold is taken as an example to illustrate the application of the proposed model. The results reveal that both the elastic modulus and the critical buckling behavior of nanoporous materials exhibit a distinct dependence on the characteristic sizes of microstructures, e.g. the average ligament width.

  17. Electrochemical fabrication of nanoporous polypyrrole thin films

    International Nuclear Information System (INIS)

    Li Mei; Yuan Jinying; Shi Gaoquan

    2008-01-01

    Polypyrrole thin films with pores in nanometer scale were synthesized by direct electrochemical oxidation of pyrrole in a mixed electrolyte of isopropyl alcohol, boron trifluoride diethyl etherate, sodium dodecylsulfonate and poly(ethylene glycol) using well-aligned ZnO nanowires arrays as templates. The thin films exhibit high conductivity of ca. σ rt ∼ 20.5 s/cm and can be driven to bend during redox processes in 1.0 M lithium perchlorate aqueous solution. The movement rate of an actuator based on this nanoporous film was measured to be over 90 o /s at a driving potential of 0.8 V (vs. Ag/AgCl)

  18. Retroreflection from nanoporous InP

    International Nuclear Information System (INIS)

    Prislopski, S.Ya.; Naumenko, E.K.; Gaponenko, S.V.; Tiginyanu, I.M.; Ghimpu, L.; Sirbu, L.; Monaico, E.

    2013-01-01

    Pronounced retroreflection behavior is reported for a fishnet nanoporous strongly absorbing semiconductor material. Retroreflection appears with diffusive specular reflection for all angles of incidence. Retroreflection is apparent by the naked eye with day light illumination and exhibits no selectivity with respect to wavelength and polarization of incident light featuring minor depolarization of retroreflected light. The phenomenon can be classified neither as coherent backscattering nor as Anderson localization of light. The primary model includes light scattering from strongly absorptive and refractive super-wavelength clusters existing within the porous fishnet structure. We found that retroreflection vanishes for wavelength where absorption becomes negligible. (authors)

  19. Fabrication of nanoporous nuclear track membranes

    International Nuclear Information System (INIS)

    Peng Liangqiang; Wang Shicheng; Ju Xin; Masaru Yoshida; Yasunari Maekawa

    2001-01-01

    Polyethylene terephthalate (PET) and polycarbonate (PC) films were irradiated by S, Kr and Xe ions and were illuminated with ultraviolet light. The normalized track etch rate for PET and PC films etched in different conditions were measured by conductometric experiments. It is shown that normalized track etch rate can be over 1000 for PET films, 2000 for PC films under optimized condition. TEM photographs of copper nanowires electroplated into nanoporous nuclear track membranes show that the narrowest wire diameter of copper nanowires is 20 nm and that the pore diameter calculated by conductometric experiments is in agreement with the wire diameter measured by TEM when the pore diameter is over 30 nm

  20. Meso-/Nanoporous Semiconducting Metal Oxides for Gas Sensor Applications

    Directory of Open Access Journals (Sweden)

    Nguyen Duc Hoa

    2015-01-01

    Full Text Available Development and/or design of new materials and/or structures for effective gas sensor applications with fast response and high sensitivity, selectivity, and stability are very important issues in the gas sensor technology. This critical review introduces our recent progress in the development of meso-/nanoporous semiconducting metal oxides and their applications to gas sensors. First, the basic concepts of resistive gas sensors and the recent synthesis of meso-/nanoporous metal oxides for gas sensor applications are introduced. The advantages of meso-/nanoporous metal oxides are also presented, taking into account the crystallinity and ordered/disordered porous structures. Second, the synthesis methods of meso-/nanoporous metal oxides including the soft-template, hard-template, and temple-free methods are introduced, in which the advantages and disadvantages of each synthetic method are figured out. Third, the applications of meso-/nanoporous metal oxides as gas sensors are presented. The gas nanosensors are designed based on meso-/nanoporous metal oxides for effective detection of toxic gases. The sensitivity, selectivity, and stability of the meso-/nanoporous gas nanosensors are also discussed. Finally, some conclusions and an outlook are presented.

  1. Modulation of Molecular Flux Using a Graphene Nanopore Capacitor.

    Science.gov (United States)

    Shankla, Manish; Aksimentiev, Aleksei

    2017-04-20

    Modulation of ionic current flowing through nanoscale pores is one of the fundamental biological processes. Inspired by nature, nanopores in synthetic solid-state membranes are being developed to enable rapid analysis of biological macromolecules and to serve as elements of nanofludic circuits. Here, we theoretically investigate ion and water transport through a graphene-insulator-graphene membrane containing a single, electrolyte-filled nanopore. By means of all-atom molecular dynamics simulations, we show that the charge state of such a graphene nanopore capacitor can regulate both the selectivity and the magnitude of the nanopore ionic current. At a fixed transmembrane bias, the ionic current can be switched from being carried by an equal mixture of cations and anions to being carried almost exclusively by either cationic or anionic species, depending on the sign of the charge assigned to both plates of the capacitor. Assigning the plates of the capacitor opposite sign charges can either increase the nanopore current or reduce it substantially, depending on the polarity of the bias driving the transmembrane current. Facilitated by the changes of the nanopore surface charge, such ionic current modulations are found to occur despite the physical dimensions of the nanopore being an order of magnitude larger than the screening length of the electrolyte. The ionic current rectification is accompanied by a pronounced electro-osmotic effect that can transport neutral molecules such as proteins and drugs across the solid-state membrane and thereby serve as an interface between electronic and chemical signals.

  2. Incorporation of sol-gel SnO2:Sb into nanoporous SiO2

    International Nuclear Information System (INIS)

    Canut, B.; Blanchin, M.G.; Ramos-Canut, S.; Teodorescu, V.; Toulemonde, M.

    2006-01-01

    Silicon oxide films thermally grown on Si(1 0 0) wafers were irradiated with 200 MeV 197 Au ions in the 10 9 -10 1 cm -2 fluence range. The targets were then etched at room temperature in aqueous HF solution (1 vol.%) for various durations. Atomic force microscopy (AFM) in the tapping mode was used to probe the processed surfaces. Conical holes with a low size dispersion were evidenced. Their surface diameter varies between 20 and 70 nm, depending on the etching time. Sol-gel dip coating technique, associated with a further annealing treatment performed at 500 o C for 15 min, was used to fill the nanopores created in SiO 2 with a transparent conductive oxide (SnO 2 doped with antimony). Transmission electron microscopy (TEM) performed on cross-sectional specimen showed that SnO 2 :Sb crystallites of ∼5 nm mean size are trapped in the holes without degrading their geometry

  3. Buckling Causes Nonlinear Dynamics of Filamentous Viruses Driven through Nanopores.

    Science.gov (United States)

    McMullen, Angus; de Haan, Hendrick W; Tang, Jay X; Stein, Derek

    2018-02-16

    Measurements and Langevin dynamics simulations of filamentous viruses driven through solid-state nanopores reveal a superlinear rise in the translocation velocity with driving force. The mobility also scales with the length of the virus in a nontrivial way that depends on the force. These dynamics are consequences of the buckling of the leading portion of a virus as it emerges from the nanopore and is put under compressive stress by the viscous forces it encounters. The leading tip of a buckled virus stalls and this reduces the total viscous drag force. We present a scaling theory that connects the solid mechanics to the nonlinear dynamics of polyelectrolytes translocating nanopores.

  4. Nanoporous carbon actuator and methods of use thereof

    Science.gov (United States)

    Biener, Juergen [San Leandro, CA; Baumann, Theodore F [Discovery Bay, CA; Shao, Lihua [Karlsruhe, DE; Weissmueller, Joerg [Stutensee, DE

    2012-07-31

    An electrochemically driveable actuator according to one embodiment includes a nanoporous carbon aerogel composition capable of exhibiting charge-induced reversible strain when wetted by an electrolyte and a voltage is applied thereto. An electrochemically driven actuator according to another embodiment includes a nanoporous carbon aerogel composition wetted by an electrolyte; and a mechanism for causing charge-induced reversible strain of the composition. A method for electrochemically actuating an object according to one embodiment includes causing charge-induced reversible strain of a nanoporous carbon aerogel composition wetted with an electrolyte to actuate the object by the strain.

  5. Nanoporous Glasses for Nuclear Waste Containment

    Directory of Open Access Journals (Sweden)

    Thierry Woignier

    2016-01-01

    Full Text Available Research is in progress to incorporate nuclear waste in new matrices with high structural stability, resistance to thermal shock, and high chemical durability. Interactions with water are important for materials used as a containment matrix for the radio nuclides. It is indispensable to improve their chemical durability to limit the possible release of radioactive chemical species, if the glass structure is attacked by corrosion. By associating high structural stability and high chemical durability, silica glass optimizes the properties of a suitable host matrix. According to an easy sintering stage, nanoporous glasses such as xerogels, aerogels, and composite gels are alternative ways to synthesize silica glass at relatively low temperatures (≈1,000–1,200°C. Nuclear wastes exist as aqueous salt solutions and we propose using the open pore structure of the nanoporous glass to enable migration of the solution throughout the solid volume. The loaded material is then sintered, thereby trapping the radioactive chemical species. The structure of the sintered materials (glass ceramics is that of nanocomposites: actinide phases (~100 nm embedded in a vitreous silica matrix. Our results showed a large improvement in the chemical durability of glass ceramic over conventional nuclear glass.

  6. Nanoporous ultrahigh specific surface polyacrylonitrile fibres

    International Nuclear Information System (INIS)

    Zhang Lifeng; Hsieh, Y-L

    2006-01-01

    The concept of phase separation was coupled with electrospinning to generate polyacrylonitrile (PAN) and poly(ethylene oxide) (PEO) bicomponent fibres that, upon removal of the phase-separated PEO domains, became nanoporous. Electrospinning of PAN (150 kDa) with 15-50% w/w PEO (10 kDa) at a 8% w/w total concentration in N,N-dimethylformamide produced fibres with decreasing averaged diameters from 390 to 130 nm. Evidence of phase separation between PAN and PEO in the bicomponent fibres was indicated by the characteristic PAN and PEO peaks by Fourier transform infrared (FTIR) spectroscopy and solid-state nuclear magnetic resonance (NMR) imaging, and confirmed by the co-existence of PAN cyclization and PEO melting by differential scanning calorimetry (DSC) and the presence of PEO crystalline diffraction by wide-angle x-ray scattering (WAXS). Removal of PEO by dissolution in water was confirmed by the matched mass loss to PEO fraction and the absence of PEO by FTIR and DSC. The water-treated bicomponent fibres appeared slightly larger in diameter and contained internal pores of nanometre scale. The nanoporous fibres generated from 50/50 PAN/PEO bicomponent precursor contained internal pores of a few nanometres to tens of nanometres in size and had 50% higher pore volume and 2.5-fold higher specific surface

  7. Structural evolution in nanoporous anodic aluminium oxide

    International Nuclear Information System (INIS)

    Rocca, Emmanuel; Vantelon, Delphine; Reguer, Solenn; Mirambet, François

    2012-01-01

    Nanoporous and self-organized layers of aluminium alloys are used in many applications as membranes, templates for nanometric objects or corrosion protection for aluminium alloys. The use of this nanometric structure widely remains empirical, especially in the case of very small pores ( 4 into AlO 6 cluster and a partial release of sulphate ions are an important chemical transformation of the amorphous structure. This structural transformation defines the chemistry (pH and surface charge) inside the nanopores, the ageing behaviour and the possible incorporation or diffusion of chemical species in the nanostructure. Highlights: ► Investigations of local chemical environment of aluminium atoms in anodic aluminium oxide. ► The oxide structure is constituted by 2/3 of aluminium in tetrahedral coordination 1/3 in octahedral coordination. ► In contact with water, AlO 4 clusters are transformed into AlO 6 cluster and the aluminium sulphate bonds are hydrolysed. ► These transformations induce a pH decrease inside the nanostructure.

  8. Cavitation and pore blocking in nanoporous glasses.

    Science.gov (United States)

    Reichenbach, C; Kalies, G; Enke, D; Klank, D

    2011-09-06

    In gas adsorption studies, porous glasses are frequently referred to as model materials for highly disordered mesopore systems. Numerous works suggest that an accurate interpretation of physisorption isotherms requires a complete understanding of network effects upon adsorption and desorption, respectively. The present article deals with nitrogen and argon adsorption at different temperatures (77 and 87 K) performed on a series of novel nanoporous glasses (NPG) with different mean pore widths. NPG samples contain smaller mesopores and significantly higher microporosity than porous Vycor glass or controlled pore glass. Since the mean pore width of NPG can be tuned sensitively, the evolution of adsorption characteristics with respect to a broadening pore network can be investigated starting from the narrowest nanopore width. With an increasing mean pore width, a H2-type hysteresis develops gradually which finally transforms into a H1-type. In this connection, a transition from a cavitation-induced desorption toward desorption controlled by pore blocking can be observed. Furthermore, we find concrete hints for a pore size dependence of the relative pressure of cavitation in highly disordered pore systems. By comparing nitrogen and argon adsorption, a comprehensive insight into adsorption mechanisms in novel disordered materials is provided. © 2011 American Chemical Society

  9. Surface engineered porous silicon for stable, high performance electrochemical supercapacitors

    Science.gov (United States)

    Oakes, Landon; Westover, Andrew; Mares, Jeremy W.; Chatterjee, Shahana; Erwin, William R.; Bardhan, Rizia; Weiss, Sharon M.; Pint, Cary L.

    2013-10-01

    Silicon materials remain unused for supercapacitors due to extreme reactivity of silicon with electrolytes. However, doped silicon materials boast a low mass density, excellent conductivity, a controllably etched nanoporous structure, and combined earth abundance and technological presence appealing to diverse energy storage frameworks. Here, we demonstrate a universal route to transform porous silicon (P-Si) into stable electrodes for electrochemical devices through growth of an ultra-thin, conformal graphene coating on the P-Si surface. This graphene coating simultaneously passivates surface charge traps and provides an ideal electrode-electrolyte electrochemical interface. This leads to 10-40X improvement in energy density, and a 2X wider electrochemical window compared to identically-structured unpassivated P-Si. This work demonstrates a technique generalizable to mesoporous and nanoporous materials that decouples the engineering of electrode structure and electrochemical surface stability to engineer performance in electrochemical environments. Specifically, we demonstrate P-Si as a promising new platform for grid-scale and integrated electrochemical energy storage.

  10. Surface engineered porous silicon for stable, high performance electrochemical supercapacitors

    Science.gov (United States)

    Oakes, Landon; Westover, Andrew; Mares, Jeremy W.; Chatterjee, Shahana; Erwin, William R.; Bardhan, Rizia; Weiss, Sharon M.; Pint, Cary L.

    2013-01-01

    Silicon materials remain unused for supercapacitors due to extreme reactivity of silicon with electrolytes. However, doped silicon materials boast a low mass density, excellent conductivity, a controllably etched nanoporous structure, and combined earth abundance and technological presence appealing to diverse energy storage frameworks. Here, we demonstrate a universal route to transform porous silicon (P-Si) into stable electrodes for electrochemical devices through growth of an ultra-thin, conformal graphene coating on the P-Si surface. This graphene coating simultaneously passivates surface charge traps and provides an ideal electrode-electrolyte electrochemical interface. This leads to 10–40X improvement in energy density, and a 2X wider electrochemical window compared to identically-structured unpassivated P-Si. This work demonstrates a technique generalizable to mesoporous and nanoporous materials that decouples the engineering of electrode structure and electrochemical surface stability to engineer performance in electrochemical environments. Specifically, we demonstrate P-Si as a promising new platform for grid-scale and integrated electrochemical energy storage. PMID:24145684

  11. Chemical Reaction Equilibrium in Nanoporous Materials: NO Dimerization Reaction in Carbon Slit Nanopores

    Czech Academy of Sciences Publication Activity Database

    Lísal, Martin; Brennan, J.K.; Smith, W.R.

    2006-01-01

    Roč. 124, č. 6 (2006), s. 64712.1-64712.14 ISSN 0021-9606 R&D Projects: GA ČR(CZ) GA203/05/0725; GA AV ČR(CZ) 1ET400720507; GA AV ČR(CZ) 1ET400720409 Institutional research plan: CEZ:AV0Z40720504 Keywords : nanopore * NO dimerization * reaction Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.166, year: 2006

  12. Nonfaradaic nanoporous electrochemistry for conductometry at high electrolyte concentration.

    Science.gov (United States)

    Bae, Je Hyun; Kang, Chung Mu; Choi, Hyoungseon; Kim, Beom Jin; Jang, Woohyuk; Lim, Sung Yul; Kim, Hee Chan; Chung, Taek Dong

    2015-02-17

    Nanoporous electrified surfaces create a unique nonfaradaic electrochemical behavior that is sensitively influenced by pore size, morphology, ionic strength, and electric field modulation. Here, we report the contributions of ion concentration and applied ac frequency to the electrode impedance through an electrical double layer overlap and ion transport along the nanopores. Nanoporous Pt with uniform pore size and geometry (L2-ePt) responded more sensitively to conductivity changes in aqueous solutions than Pt black with poor uniformity despite similar real surface areas and enabled the previously difficult quantitative conductometry measurements at high electrolyte concentrations. The nanopores of L2-ePt were more effective in reducing the electrode impedance and exhibited superior linear responses to not only flat Pt but also Pt black, leading to successful conductometric detection in ion chromatography without ion suppressors and at high ionic strengths.

  13. Information Dynamics of a Nonlinear Stochastic Nanopore System

    Directory of Open Access Journals (Sweden)

    Claire Gilpin

    2018-03-01

    Full Text Available Nanopores have become a subject of interest in the scientific community due to their potential uses in nanometer-scale laboratory and research applications, including infectious disease diagnostics and DNA sequencing. Additionally, they display behavioral similarity to molecular and cellular scale physiological processes. Recent advances in information theory have made it possible to probe the information dynamics of nonlinear stochastic dynamical systems, such as autonomously fluctuating nanopore systems, which has enhanced our understanding of the physical systems they model. We present the results of local (LER and specific entropy rate (SER computations from a simulation study of an autonomously fluctuating nanopore system. We learn that both metrics show increases that correspond to fluctuations in the nanopore current, indicating fundamental changes in information generation surrounding these fluctuations.

  14. Side-gated ultrathin-channel nanopore FET sensors

    International Nuclear Information System (INIS)

    Yanagi, Itaru; Haga, Takanobu; Ando, Masahiko; Yamamoto, Jiro; Mine, Toshiyuki; Ishida, Takeshi; Hatano, Toshiyuki; Akahori, Rena; Yokoi, Takahide; Anazawa, Takashi; Oura, Takeshi

    2016-01-01

    A side-gated, ultrathin-channel nanopore FET (SGNAFET) is proposed for fast and label-free DNA sequencing. The concept of the SGNAFET comprises the detection of changes in the channel current during DNA translocation through a nanopore and identifying the four types of nucleotides as a result of these changes. To achieve this goal, both p- and n-type SGNAFETs with a channel thicknesses of 2 or 4 nm were fabricated, and the stable transistor operation of both SGNAFETs in air, water, and a KCl buffer solution were confirmed. In addition, synchronized current changes were observed between the ionic current through the nanopore and the SGNAFET’s drain current during DNA translocation through the nanopore. (paper)

  15. Hydrophilic nanoporous polystyrenes and 1,2-polybutadienes

    DEFF Research Database (Denmark)

    Guo, Fengxiao; Jankova Atanasova, Katja; Vigild, Martin Etchells

    2008-01-01

    Nanoporous polymers from ordered block copolymers having hydrophilic cavity surfaces were successfully prepared by two methodologies: ' 1. Nanoporous polystyrenes fromPtBA-b-PS diblock or PDMS-b-PtBA-b-PS triblock copolymer precursors by atom transfer radical polymerization (ATRP), or combination...... of living anionic polymerization~ and ATRP r~spectively. The one, PtBA block, can be modified to the hydrophilic PAA, where the dther, polydimethysiloxane (PDMS) block, can be fully degraded. Deprotection of the tert-butyl groups in PtBA and the selective etching of PDMS· chains were accomplished...... by applying HF or TFA in one step. Thus both the di- and triblock copolymers after such a treatment resulted. in nanoporous polystyrenes with hexagonal cavities of different nanosizes (6-11 nm, Figure 1). 2. Nanoporous I,2-polybutadienes (I,2-PB) by grafting various acrylic monomers onto the pore. surfaces...

  16. Stable lithium electrodeposition in liquid and nanoporous solid electrolytes

    KAUST Repository

    Lu, Yingying; Tu, Zhengyuan; Archer, Lynden A.

    2014-01-01

    of these metals and their inability to form uniform electrodeposits on surfaces with inevitable defects. We report on electrodeposition of lithium in simple liquid electrolytes and in nanoporous solids infused with liquid electrolytes. We find that simple liquid

  17. Multistep Current Signal in Protein Translocation through Graphene Nanopores

    KAUST Repository

    Bonome, Emma Letizia; Lepore, Rosalba; Raimondo, Domenico; Cecconi, Fabio; Tramontano, Anna; Chinappi, Mauro

    2015-01-01

    of graphene constitute a major advantage for molecule characterization. Here we analyze the translocation pathway of the thioredoxin protein across a graphene nanopore, and the related ionic currents, by integrating two nonequilibrium molecular dynamics

  18. Nanoporous Polymer-Ceramic Composite Electrolytes for Lithium Metal Batteries

    KAUST Repository

    Tu, Zhengyuan; Kambe, Yu; Lu, Yingying; Archer, Lynden A.

    2013-01-01

    A nanoporous composite material that offers the unique combination of high room-temperature ionic conductivity and high mechanical modulus is reported. When used as the separator/electrolyte in lithium batteries employing metallic lithium as anode

  19. Capacitance-Power-Hysteresis Trilemma in Nanoporous Supercapacitors

    OpenAIRE

    Lee, Alpha A; Vella, Dominic; Goriely, Alain; Kondrat, Svyatoslav

    2015-01-01

    Nanoporous supercapacitors are an important player in the field of energy storage that fill the gap between dielectric capacitors and batteries. The key challenge in the development of supercapacitors is the perceived trade-off between capacitance and power delivery. Current efforts to boost the capacitance of nanoporous supercapacitors focus on reducing the pore size so that they can only accommodate a single layer of ions. However, this tight packing compromises the charging dynamics and he...

  20. Nanoporous ionic organic networks: from synthesis to materials applications

    OpenAIRE

    Sun, Jian-Ke; Antonietti, Markus; Yuan, Jiayin

    2016-01-01

    The past decade has witnessed rapid progress in the synthesis of nanoporous organic networks or polymer frameworks for various potential applications. Generally speaking, functionalization of porous networks to add extra properties and enhance materials performance could be achieved either during the pore formation (thus a concurrent approach) or by post-synthetic modification (a sequential approach). Nanoporous organic networks which include ion pairs bound in a covalent manner are of specia...

  1. Polyelectrolyte layer-by-layer deposition in cylindrical nanopores.

    Science.gov (United States)

    Lazzara, Thomas D; Lau, K H Aaron; Abou-Kandil, Ahmed I; Caminade, Anne-Marie; Majoral, Jean-Pierre; Knoll, Wolfgang

    2010-07-27

    Layer-by-layer (LbL) deposition of polyelectrolytes within nanopores in terms of the pore size and the ionic strength was experimentally studied. Anodic aluminum oxide (AAO) membranes, which have aligned, cylindrical, nonintersecting pores, were used as a model nanoporous system. Furthermore, the AAO membranes were also employed as planar optical waveguides to enable in situ monitoring of the LbL process within the nanopores by optical waveguide spectroscopy (OWS). Structurally well-defined N,N-disubstituted hydrazine phosphorus-containing dendrimers of the fourth generation, with peripherally charged groups and diameters of approximately 7 nm, were used as the model polyelectrolytes. The pore diameter of the AAO was varied between 30-116 nm and the ionic strength was varied over 3 orders of magnitude. The dependence of the deposited layer thickness on ionic strength within the nanopores is found to be significantly stronger than LbL deposition on a planar surface. Furthermore, deposition within the nanopores can become inhibited even if the pore diameter is much larger than the diameter of the G4-polyelectrolyte, or if the screening length is insignificant relative to the dendrimer diameter at high ionic strengths. Our results will aid in the template preparation of polyelectrolyte multilayer nanotubes, and our experimental approach may be useful for investigating theories regarding the partitioning of nano-objects within nanopores where electrostatic interactions are dominant. Furthermore, we show that the enhanced ionic strength dependence of polyelectrolyte transport within the nanopores can be used to selectively deposit a LbL multilayer atop a nanoporous substrate.

  2. Nanotopography effects on astrocyte attachment to nanoporous gold surfaces.

    Science.gov (United States)

    Kurtulus, Ozge; Seker, Erkin

    2012-01-01

    Nanoporous gold, synthesized by a self-assembly process, is a new biomaterial with desirable attributes, including tunable nanotopography, drug delivery potential, electrical conductivity, and compatibility with conventional microfabrication techniques. This study reports on the effect of nanotopography in guiding cellular attachment on nanoporous gold surfaces. While the changes in topography do not affect adherent cell density, average cell area displays a non-monotonic dependence on nanotopography.

  3. Applications of Synthetic Microchannel and Nanopore Systems

    Science.gov (United States)

    Hinkle, Thomas Preston

    This thesis describes research conducted on the physics and applications of micro- and nanoscale ion-conducting channels. Making use of the nanoscale physics that takes place in the vicinity of charged surfaces, there is the possibility that nanopores, holes on the order of 1 nm in size, could be used to make complex integrated ionic circuits. For inspiration on what such circuits could achieve we only need to look to biology systems, immensely complex machines that at their most basic level require precise control of ions and intercellular electric potentials to function. In order to contribute to the ever expanding field of nanopore research, we engineered novel hybrid insulator-conductor nanopores that behave analagously to ionic diodes, which allow passage of current flow in one direction but severely limit the current in the opposite direction. The experiments revealed that surface polarization of the conducting material can induce the formation of an electrical double layer in the same way static surface charges can. Furthermore, we showed that the hybrid device behaved similar to an ionic diode, and could see potential use as a standard rectifying element in ionic circuits. Another application based on ion conducting channels is resistive pulse sensing, a single particle detection and characterization method. We present three main experiments that expand the capacity of resistive pulse sensing for particle characterization. First, we demonstrate how resistive pulse sensing in pores with longitudinal irregularities can be used to measure the lengths of individual nanoparticles. Then, we describe an entirely new hybrid approach to resistive pulse sensing, whereby the electrical measurements are combined with simultaneous optical imaging. The hybrid method allows for validation of the resistive pulse signals and will greatly contribute to their interpretability. We present experiments that explore some of the possibilities of the hybrid method. Then, building

  4. DNA Origami-Graphene Hybrid Nanopore for DNA Detection.

    Science.gov (United States)

    Barati Farimani, Amir; Dibaeinia, Payam; Aluru, Narayana R

    2017-01-11

    DNA origami nanostructures can be used to functionalize solid-state nanopores for single molecule studies. In this study, we characterized a nanopore in a DNA origami-graphene heterostructure for DNA detection. The DNA origami nanopore is functionalized with a specific nucleotide type at the edge of the pore. Using extensive molecular dynamics (MD) simulations, we computed and analyzed the ionic conductivity of nanopores in heterostructures carpeted with one or two layers of DNA origami on graphene. We demonstrate that a nanopore in DNA origami-graphene gives rise to distinguishable dwell times for the four DNA base types, whereas for a nanopore in bare graphene, the dwell time is almost the same for all types of bases. The specific interactions (hydrogen bonds) between DNA origami and the translocating DNA strand yield different residence times and ionic currents. We also conclude that the speed of DNA translocation decreases due to the friction between the dangling bases at the pore mouth and the sequencing DNA strands.

  5. Synthesis and electrochemical study of Pt-based nanoporous materials

    International Nuclear Information System (INIS)

    Wang Jingpeng; Holt-Hindle, Peter; MacDonald, Duncan; Thomas, Dan F.; Chen Aicheng

    2008-01-01

    In the present work, a variety of Pt-based bimetallic nanostructured materials including nanoporous Pt, Pt-Ru, Pt-Ir, Pt-Pd and Pt-Pb networks have been directly grown on titanium substrates via a facile hydrothermal method. The as-fabricated electrodes were characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction and electrochemical methods. The active surface areas of these nanoporous Pt-based alloy catalysts are increased by over 68 (Pt-Pd), 69 (Pt-Ru) and 113 (Pt-Ir) fold compared to a polycrystalline Pt electrode. All these synthesized nanoporous electrodes exhibit superb electrocatalytic performance towards electrochemical oxidation of methanol and formic acid. Among the five nanoporous Pt-based electrodes, the Pt-Ir shows the highest peak current density at +0.50 V, with 68 times of enhancement compared to the polycrystalline Pt for methanol oxidation, and with 86 times of enhancement in formic acid oxidation; whereas the catalytic activity of the nanoporous Pt-Pb electrode outperforms the other materials in formic acid oxidation at the low potential regions, delivering an enhanced current density by 280-fold compared to the polycrystalline Pt at +0.15 V. The new approach described in this study is suitable for synthesizing a wide range of bi-metallic and tri-metallic nanoporous materials, desirable for electrochemical sensor design and potential application in fuel cells

  6. Synthesis and electrochemical study of Pt-based nanoporous materials

    Energy Technology Data Exchange (ETDEWEB)

    Wang Jingpeng [Department of Chemistry, Lakehead University, Thunder Bay, Ontario P7B 5E1 (Canada); Department of Chemistry, University of Guelph, Guelph, Ontario N1G 2W1 (Canada); Holt-Hindle, Peter; MacDonald, Duncan [Department of Chemistry, Lakehead University, Thunder Bay, Ontario P7B 5E1 (Canada); Thomas, Dan F. [Department of Chemistry, University of Guelph, Guelph, Ontario N1G 2W1 (Canada); Chen Aicheng [Department of Chemistry, Lakehead University, Thunder Bay, Ontario P7B 5E1 (Canada)], E-mail: aicheng.chen@lakeheadu.ca

    2008-10-01

    In the present work, a variety of Pt-based bimetallic nanostructured materials including nanoporous Pt, Pt-Ru, Pt-Ir, Pt-Pd and Pt-Pb networks have been directly grown on titanium substrates via a facile hydrothermal method. The as-fabricated electrodes were characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction and electrochemical methods. The active surface areas of these nanoporous Pt-based alloy catalysts are increased by over 68 (Pt-Pd), 69 (Pt-Ru) and 113 (Pt-Ir) fold compared to a polycrystalline Pt electrode. All these synthesized nanoporous electrodes exhibit superb electrocatalytic performance towards electrochemical oxidation of methanol and formic acid. Among the five nanoporous Pt-based electrodes, the Pt-Ir shows the highest peak current density at +0.50 V, with 68 times of enhancement compared to the polycrystalline Pt for methanol oxidation, and with 86 times of enhancement in formic acid oxidation; whereas the catalytic activity of the nanoporous Pt-Pb electrode outperforms the other materials in formic acid oxidation at the low potential regions, delivering an enhanced current density by 280-fold compared to the polycrystalline Pt at +0.15 V. The new approach described in this study is suitable for synthesizing a wide range of bi-metallic and tri-metallic nanoporous materials, desirable for electrochemical sensor design and potential application in fuel cells.0.

  7. Synthesis and electrochemical study of Pt-based nanoporous materials

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jingpeng [Department of Chemistry, Lakehead University, Thunder Bay, Ontario P7B 5E1 (Canada); Department of Chemistry, University of Guelph, Guelph, Ontario N1G 2W1 (Canada); Holt-Hindle, Peter; MacDonald, Duncan; Chen, Aicheng [Department of Chemistry, Lakehead University, Thunder Bay, Ontario P7B 5E1 (Canada); Thomas, Dan F. [Department of Chemistry, University of Guelph, Guelph, Ontario N1G 2W1 (Canada)

    2008-10-01

    In the present work, a variety of Pt-based bimetallic nanostructured materials including nanoporous Pt, Pt-Ru, Pt-Ir, Pt-Pd and Pt-Pb networks have been directly grown on titanium substrates via a facile hydrothermal method. The as-fabricated electrodes were characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction and electrochemical methods. The active surface areas of these nanoporous Pt-based alloy catalysts are increased by over 68 (Pt-Pd), 69 (Pt-Ru) and 113 (Pt-Ir) fold compared to a polycrystalline Pt electrode. All these synthesized nanoporous electrodes exhibit superb electrocatalytic performance towards electrochemical oxidation of methanol and formic acid. Among the five nanoporous Pt-based electrodes, the Pt-Ir shows the highest peak current density at +0.50 V, with 68 times of enhancement compared to the polycrystalline Pt for methanol oxidation, and with 86 times of enhancement in formic acid oxidation; whereas the catalytic activity of the nanoporous Pt-Pb electrode outperforms the other materials in formic acid oxidation at the low potential regions, delivering an enhanced current density by 280-fold compared to the polycrystalline Pt at +0.15 V. The new approach described in this study is suitable for synthesizing a wide range of bi-metallic and tri-metallic nanoporous materials, desirable for electrochemical sensor design and potential application in fuel cells. (author)

  8. Streaming current magnetic fields in a charged nanopore

    Science.gov (United States)

    Mansouri, Abraham; Taheri, Peyman; Kostiuk, Larry W.

    2016-01-01

    Magnetic fields induced by currents created in pressure driven flows inside a solid-state charged nanopore were modeled by numerically solving a system of steady state continuum partial differential equations, i.e., Poisson, Nernst-Planck, Ampere and Navier-Stokes equations (PNPANS). This analysis was based on non-dimensional transport governing equations that were scaled using Debye length as the characteristic length scale, and applied to a finite length cylindrical nano-channel. The comparison of numerical and analytical studies shows an excellent agreement and verified the magnetic fields density both inside and outside the nanopore. The radially non-uniform currents resulted in highly non-uniform magnetic fields within the nanopore that decay as 1/r outside the nanopore. It is worth noting that for either streaming currents or streaming potential cases, the maximum magnetic field occurred inside the pore in the vicinity of nanopore wall, as opposed to a cylindrical conductor that carries a steady electric current where the maximum magnetic fields occur at the perimeter of conductor. Based on these results, it is suggested and envisaged that non-invasive external magnetic fields readouts generated by streaming/ionic currents may be viewed as secondary electronic signatures of biomolecules to complement and enhance current DNA nanopore sequencing techniques. PMID:27833119

  9. Antibacterial activity of zinc oxide-coated nanoporous alumina

    Energy Technology Data Exchange (ETDEWEB)

    Skoog, S.A. [Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Box 7115, Raleigh, NC 27695-7115 (United States); Bayati, M.R. [Department of Materials Science and Engineering, North Carolina State University, Box 7907, Raleigh, NC 27695-7907 (United States); Petrochenko, P.E. [Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Box 7115, Raleigh, NC 27695-7115 (United States); Division of Biology, Office of Science and Engineering Laboratories, Center for Devices and Radiological Health, U.S. Food and Drug Administration, Silver Spring, MD 20993 (United States); Stafslien, S.; Daniels, J.; Cilz, N. [Center for Nanoscale Science and Engineering, North Dakota State University, 1805 Research Park Drive, Fargo, ND 58102 (United States); Comstock, D.J.; Elam, J.W. [Energy Systems Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Narayan, R.J., E-mail: roger_narayan@msn.com [Joint Department of Biomedical Engineering, University of North Carolina and North Carolina State University, Box 7115, Raleigh, NC 27695-7115 (United States); Department of Materials Science and Engineering, North Carolina State University, Box 7907, Raleigh, NC 27695-7907 (United States)

    2012-07-25

    Highlights: Black-Right-Pointing-Pointer Atomic layer deposition was used to deposit ZnO on nanoporous alumina membranes. Black-Right-Pointing-Pointer Scanning electron microscopy showed continuous coatings of zinc oxide nanocrystals. Black-Right-Pointing-Pointer Activity against B. subtilis, E. coli, S. aureus, and S. epidermidis was shown. - Abstract: Nanoporous alumina membranes, also known as anodized aluminum oxide membranes, are being investigated for use in treatment of burn injuries and other skin wounds. In this study, atomic layer deposition was used for coating the surfaces of nanoporous alumina membranes with zinc oxide. Agar diffusion assays were used to show activity of zinc oxide-coated nanoporous alumina membranes against several bacteria found on the skin surface, including Bacillus subtilis, Escherichia coli, Staphylococcus aureus, and Staphylococcus epidermidis. On the other hand, zinc oxide-coated nanoporous alumina membranes did not show activity against Pseudomonas aeruginosa, Enterococcus faecalis, and Candida albicans. These results suggest that zinc oxide-coated nanoporous alumina membranes have activity against some Gram-positive and Gram-negative bacteria that are associated with skin colonization and skin infection.

  10. Impedance nanopore biosensor: influence of pore dimensions on biosensing performance.

    Science.gov (United States)

    Kant, Krishna; Yu, Jingxian; Priest, Craig; Shapter, Joe G; Losic, Dusan

    2014-03-07

    Knowledge about electrochemical and electrical properties of nanopore structures and the influence of pore dimensions on these properties is important for the development of nanopore biosensing devices. The aim of this study was to explore the influence of nanopore dimensions (diameter and length) on biosensing performance using non-faradic electrochemical impedance spectroscopy (EIS). Nanoporous alumina membranes (NPAMs) prepared by self-ordered electrochemical anodization of aluminium were used as model nanopore sensing platforms. NPAMs with different pore diameters (25-65 nm) and lengths (4-18 μm) were prepared and the internal pore surface chemistry was modified by covalently attaching streptavidin and biotin. The performance of this antibody nanopore biosensing platform was evaluated using various concentrations of biotin as a model analyte. EIS measurements of pore resistivity and conductivity were carried out for pores with different diameters and lengths. The results showed that smaller pore dimensions of 25 nm and pore lengths up to 10 μm provide better biosensing performance.

  11. Biological Nanopores: Confined Spaces for Electrochemical Single-Molecule Analysis.

    Science.gov (United States)

    Cao, Chan; Long, Yi-Tao

    2018-02-20

    Nanopore sensing is developing into a powerful single-molecule approach to investigate the features of biomolecules that are not accessible by studying ensemble systems. When a target molecule is transported through a nanopore, the ions occupying the pore are excluded, resulting in an electrical signal from the intermittent ionic blockade event. By statistical analysis of the amplitudes, duration, frequencies, and shapes of the blockade events, many properties of the target molecule can be obtained in real time at the single-molecule level, including its size, conformation, structure, charge, geometry, and interactions with other molecules. With the development of the use of α-hemolysin to characterize individual polynucleotides, nanopore technology has attracted a wide range of research interest in the fields of biology, physics, chemistry, and nanoscience. As a powerful single-molecule analytical method, nanopore technology has been applied for the detection of various biomolecules, including oligonucleotides, peptides, oligosaccharides, organic molecules, and disease-related proteins. In this Account, we highlight recent developments of biological nanopores in DNA-based sensing and in studying the conformational structures of DNA and RNA. Furthermore, we introduce the application of biological nanopores to investigate the conformations of peptides affected by charge, length, and dipole moment and to study disease-related proteins' structures and aggregation transitions influenced by an inhibitor, a promoter, or an applied voltage. To improve the sensing ability of biological nanopores and further extend their application to a wider range of molecular sensing, we focus on exploring novel biological nanopores, such as aerolysin and Stable Protein 1. Aerolysin exhibits an especially high sensitivity for the detection of single oligonucleotides both in current separation and duration. Finally, to facilitate the use of nanopore measurements and statistical analysis

  12. Electrochemical fabrication of nanoporous polypyrrole thin films

    Energy Technology Data Exchange (ETDEWEB)

    Li Mei [Key Laboratory of Organic Optoelectronics and Molecular Engineering (Ministry of Education), Department of Chemistry, Tsinghua University, Beijing, 100084 (China); Yuan Jinying [Key Laboratory of Organic Optoelectronics and Molecular Engineering (Ministry of Education), Department of Chemistry, Tsinghua University, Beijing, 100084 (China)], E-mail: yuanjy@mail.tsinghua.edu.cn; Shi Gaoquan [Key Laboratory of Organic Optoelectronics and Molecular Engineering (Ministry of Education), Department of Chemistry, Tsinghua University, Beijing, 100084 (China)], E-mail: gshi@mail.tsinghua.edu.cn

    2008-04-30

    Polypyrrole thin films with pores in nanometer scale were synthesized by direct electrochemical oxidation of pyrrole in a mixed electrolyte of isopropyl alcohol, boron trifluoride diethyl etherate, sodium dodecylsulfonate and poly(ethylene glycol) using well-aligned ZnO nanowires arrays as templates. The thin films exhibit high conductivity of ca. {sigma}{sub rt} {approx} 20.5 s/cm and can be driven to bend during redox processes in 1.0 M lithium perchlorate aqueous solution. The movement rate of an actuator based on this nanoporous film was measured to be over 90{sup o}/s at a driving potential of 0.8 V (vs. Ag/AgCl)

  13. Nanoporous-carbon films for microsensor preconcentrators

    Science.gov (United States)

    Siegal, M. P.; Overmyer, D. L.; Kottenstette, R. J.; Tallant, D. R.; Yelton, W. G.

    2002-05-01

    Nanoporous-carbon (NPC) films are grown using physical processes such as low-power pulsed-laser deposition with attenuation of the ablated carbon species kinetic energy attained by using an inert background gas. With room-temperature growth and negligible residual stress, NPC can coat nearly any substrate to any desired thickness. Control of the deposition energetics yields precise morphology, density, and hence, porosity, with no discernable variation in chemical bonding. We produce NPC films 8 μm thick with density <0.2 g/cm3. The well-controlled porosity, i.e., available surface area, is demonstrated by using films with different thicknesses as a preconcentrator for a nerve-gas simulant.

  14. High Capacity Hydrogen Storage on Nanoporous Biocarbon

    Science.gov (United States)

    Burress, Jacob; Wood, Mikael; Gordon, Michael; Parilla, Phillip; Benham, Michael; Wexler, Carlos; Hawthorne, Fred; Pfeifer, Peter

    2008-03-01

    The Alliance for Collaborative Research in Alternative Fuel Technology (http://all-craft.missouri.edu) has been optimizing nanoporous biocarbon for high capacity hydrogen storage. The hydrogen storage was measured gravimetrically and volumetrically (Sievert's apparatus). These measurements have been validated by NREL and Hiden Isochema. Sample S-33/k, our current best performer, stores 73-91 g H2/kg carbon at 77 K and 47 bar, and 1.0-1.6 g H2/kg carbon at 293 K and 47 bar. Hydrogen isotherms run by Hiden Isochema have given experimental binding energies of 8.8 kJ/mol compared to the binding energy of graphite of 5 kJ/mol. Results from a novel boron doping technique will also be presented. The benefits and validity of using boron-doping on carbon will also be discussed.

  15. Rapid resistome mapping using nanopore sequencing.

    Science.gov (United States)

    van der Helm, Eric; Imamovic, Lejla; Hashim Ellabaan, Mostafa M; van Schaik, Willem; Koza, Anna; Sommer, Morten O A

    2017-05-05

    The emergence of antibiotic resistance in human pathogens has become a major threat to modern medicine. The outcome of antibiotic treatment can be affected by the composition of the gut. Accordingly, knowledge of the gut resistome composition could enable more effective and individualized treatment of bacterial infections. Yet, rapid workflows for resistome characterization are lacking. To address this challenge we developed the poreFUME workflow that deploys functional metagenomic selections and nanopore sequencing to resistome mapping. We demonstrate the approach by functionally characterizing the gut resistome of an ICU (intensive care unit) patient. The accuracy of the poreFUME pipeline is with >97% sufficient for the annotation of antibiotic resistance genes. The poreFUME pipeline provides a promising approach for efficient resistome profiling that could inform antibiotic treatment decisions in the future. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

  16. Ultrafiltration by gyroid nanoporous polymer membranes

    DEFF Research Database (Denmark)

    Li, Li; Szewczykowski, Piotr Przemyslaw; Clausen, Lydia D.

    2011-01-01

    the effect of membrane fouling on the flux decline and rejection profiles. Significant fouling occurred in the case of hydrophobic membranes in contact with water solutions, while in the presence of high concentration of ethanol in the filtration solution and in the case of hydrophilized membranes...... the fouling was reduced. The observed rejection of PEG was compared with theoretic predictions, as described by the Bungay–Brenner model. The model satisfactorily described the rejection profile of PEG up to 12kg/mol through hydrophobic membranes in the presence of excess ethanol. A significantly reduced......Gyroid nanoporous cross-linked 1,2-polybutadiene membranes with uniform pores were developed for ultrafiltration applications. The gyroid porosity has the advantage of isotropic percolation with no need for structure pre-alignment. The effects of solvent and surface photo...

  17. Multilayer Nanoporous Graphene Membranes for Water Desalination.

    Science.gov (United States)

    Cohen-Tanugi, David; Lin, Li-Chiang; Grossman, Jeffrey C

    2016-02-10

    While single-layer nanoporous graphene (NPG) has shown promise as a reverse osmosis (RO) desalination membrane, multilayer graphene membranes can be synthesized more economically than the single-layer material. In this work, we build upon the knowledge gained to date toward single-layer graphene to explore how multilayer NPG might serve as a RO membrane in water desalination using classical molecular dynamic simulations. We show that, while multilayer NPG exhibits similarly promising desalination properties to single-layer membranes, their separation performance can be designed by manipulating various configurational variables in the multilayer case. This work establishes an atomic-level understanding of the effects of additional NPG layers, layer separation, and pore alignment on desalination performance, providing useful guidelines for the design of multilayer NPG membranes.

  18. Biomimetic glass nanopores employing aptamer gates responsive to a small molecule†

    Science.gov (United States)

    Abelow, Alexis E.; Schepelina, Olga; White, Ryan J.; Vallée-Bélisle, Alexis

    2011-01-01

    We report the preparation of 20 and 65 nm radii glass nanopores whose surface is modified with DNA aptamers controlling the molecular transport through the nanopores in response to small molecule binding. PMID:20865192

  19. Hybrid matrices of TiO2 and TiO2–Ag nanofibers with silicone for high water flux photocatalytic degradation of dairy effluent

    DEFF Research Database (Denmark)

    Kanjwal, Muzafar Ahmad; Alm, Martin; Thomsen, Peter

    2016-01-01

    TiO2 and TiO2–Ag nanofibers were produced by electrospinning technique and surface coated on silicone elastomer (diameter: 10.0 mm; thickness: 2.0 mm) by dipcoating method. These coated hybrid nanoporous matrices were characterized by various morphological and physicochemical techniques (like SEM...

  20. A new view of microcrystalline silicon: The role of plasma processing in achieving a dense and stable absorber material for photovoltaic applicationsv

    Czech Academy of Sciences Publication Activity Database

    Bugnon, G.; Parascandolo, G.; Söderström, T.; Cuony, P.; Despeisse, M.; Hänni, S.; Holovský, Jakub; Meillaud, F.; Ballif, C.

    2012-01-01

    Roč. 22, č. 17 (2012), s. 3665-3671 ISSN 1616-301X Institutional research plan: CEZ:AV0Z10100521 Keywords : solar cell * microcrystalline silicon * nanoporous Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 9.765, year: 2012 http://onlinelibrary.wiley.com/doi/10.1002/adfm.201200299/pdf

  1. Fluid Behavior and Fluid-Solid Interactions in Nanoporous Media

    Science.gov (United States)

    Xu, H.

    2015-12-01

    Although shale oil/gas production in the US has increased exponentially, the low energy recovery is a daunting problem needed to be solved for its sustainability and continued growth, especially in light of the recent oil/gas price decline. This is apparently related to the small porosity (a few to a few hundred nm) and low permeability (10-16-10-20 m2) of tight shale formations. The fundamental question lies in the anomalous behavior of fluids in nanopores due to confinement effects, which, however, remains poorly understood. In this study, we combined experimental characterization and observations, particularly using small-angle neutron scattering (SANS), with pore-scale modeling using lattice Boltzmann method (LBM), to examine the fluid behavior and fluid-solid interactions in nanopores at reservoir conditions. Experimentally, we characterized the compositions and microstructures of a shale sample from Wolfcamp, Texas, using a variety of analytical techniques. Our analyses reveal that the shale sample is made of organic-matter (OM)-lean and OM-rich layers that exhibit different chemical and mineral compositions, and microstructural characteristics. Using the hydrostatic pressure system and gas-mixing setup we developed, in-situ SANS measurements were conducted at pressures up to 20 kpsi on shale samples imbibed with water or water-methane solutions. The obtained results indicate that capillary effect plays a significant role in fluid-nanopore interactions and the associated changes in nanopore structures vary with pore size and pressure. Computationally, we performed LBM modeling to simulate the flow behavior of methane in kerogen nanoporous structure. The correction factor, which is the ratio of apparent permeability to intrinsic permeability, was calculated. Our results show that the correction factor is always greater than one (non-continuum/non-Darcy effects) and increases with decreasing nanopore size, intrinsic permeability and pressure. Hence, the

  2. Si Nanopores Development for External Control of Transport of Biomolecules

    Energy Technology Data Exchange (ETDEWEB)

    Ileri, N; Tringe, J; Letant, S; Palozoglu, A; Stroeve, P; Faller, R

    2008-06-13

    Nazar Ileri has been involved in an independent, multidisciplinary effort to create a new class of molecular sieves for proteins and viruses. Her experimental work has been performed concurrently at two campuses, LLNL and UC Davis, while theoretical components have been largely accomplished at UC Davis. As will be described, the devices she is creating have great potential to improve very significantly the efficiency and selectivity of molecular transport over what is presently available from state-of-the-art membranes. Our biotechnology training program is based on an integrated study of the transport of biomolecules through conically-shaped, nanoporous silicon membranes. The overall objective of this effort is to demonstrate an efficient, highly selective membrane technology that is manufacturable for macroscopic areas and can be employed in sensing, diagnostic and biomedical applications. Our specific aims are to (1) fabricate and characterize the physical characteristics of the membranes, (2) to demonstrate their utility for molecular transport and separation, and (3) to develop models that will facilitate understanding of these devices as well as improved performance of the next generation of devices. We have proposed that the conical pores have superior performance characteristics compared to other porous filters. To study this hypothesis, complementary approaches from different disciplines, such as membrane synthesis, experiment, and molecular simulation need to be combined. This provides an ideal training environment for a future leader in biotechnology. Hence, for this study, Nazar Ileri has started to carry out a full range of experimental and theoretical investigations under our guidance. First, she has begun fabrication of filters with conical/pyramidal pores. She characterized the pores by AFM and SEM, and analyzed the images using wavelets and other mathematical tools. She has also started to conduct biomolecule transport experiments to compare the

  3. Si Nanopores Development for External Control of Transport of Biomolecules

    International Nuclear Information System (INIS)

    Ileri, N.; Tringe, J.; Letant, S.; Palozoglu, A.; Stroeve, P.; Faller, R.

    2008-01-01

    Nazar Ileri has been involved in an independent, multidisciplinary effort to create a new class of molecular sieves for proteins and viruses. Her experimental work has been performed concurrently at two campuses, LLNL and UC Davis, while theoretical components have been largely accomplished at UC Davis. As will be described, the devices she is creating have great potential to improve very significantly the efficiency and selectivity of molecular transport over what is presently available from state-of-the-art membranes. Our biotechnology training program is based on an integrated study of the transport of biomolecules through conically-shaped, nanoporous silicon membranes. The overall objective of this effort is to demonstrate an efficient, highly selective membrane technology that is manufacturable for macroscopic areas and can be employed in sensing, diagnostic and biomedical applications. Our specific aims are to (1) fabricate and characterize the physical characteristics of the membranes, (2) to demonstrate their utility for molecular transport and separation, and (3) to develop models that will facilitate understanding of these devices as well as improved performance of the next generation of devices. We have proposed that the conical pores have superior performance characteristics compared to other porous filters. To study this hypothesis, complementary approaches from different disciplines, such as membrane synthesis, experiment, and molecular simulation need to be combined. This provides an ideal training environment for a future leader in biotechnology. Hence, for this study, Nazar Ileri has started to carry out a full range of experimental and theoretical investigations under our guidance. First, she has begun fabrication of filters with conical/pyramidal pores. She characterized the pores by AFM and SEM, and analyzed the images using wavelets and other mathematical tools. She has also started to conduct biomolecule transport experiments to compare the

  4. Silicon Qubits

    Energy Technology Data Exchange (ETDEWEB)

    Ladd, Thaddeus D. [HRL Laboratories, LLC, Malibu, CA (United States); Carroll, Malcolm S. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2018-02-28

    Silicon is a promising material candidate for qubits due to the combination of worldwide infrastructure in silicon microelectronics fabrication and the capability to drastically reduce decohering noise channels via chemical purification and isotopic enhancement. However, a variety of challenges in fabrication, control, and measurement leaves unclear the best strategy for fully realizing this material’s future potential. In this article, we survey three basic qubit types: those based on substitutional donors, on metal-oxide-semiconductor (MOS) structures, and on Si/SiGe heterostructures. We also discuss the multiple schema used to define and control Si qubits, which may exploit the manipulation and detection of a single electron charge, the state of a single electron spin, or the collective states of multiple spins. Far from being comprehensive, this article provides a brief orientation to the rapidly evolving field of silicon qubit technology and is intended as an approachable entry point for a researcher new to this field.

  5. Single molecule transistor based nanopore for the detection of nicotine

    Energy Technology Data Exchange (ETDEWEB)

    Ray, S. J., E-mail: ray.sjr@gmail.com [Institute of Materials Science, Technical University of Darmstadt, Alarich-Weiss-Str. 2, 64287 Darmstadt (Germany)

    2014-12-28

    A nanopore based detection methodology was proposed and investigated for the detection of Nicotine. This technique uses a Single Molecular Transistor working as a nanopore operational in the Coulomb Blockade regime. When the Nicotine molecule is pulled through the nanopore area surrounded by the Source(S), Drain (D), and Gate electrodes, the charge stability diagram can detect the presence of the molecule and is unique for a specific molecular structure. Due to the weak coupling between the different electrodes which is set by the nanopore size, the molecular energy states stay almost unaffected by the electrostatic environment that can be realised from the charge stability diagram. Identification of different orientation and position of the Nicotine molecule within the nanopore area can be made from specific regions of overlap between different charge states on the stability diagram that could be used as an electronic fingerprint for detection. This method could be advantageous and useful to detect the presence of Nicotine in smoke which is usually performed using chemical chromatography techniques.

  6. Biomimetic novel nanoporous niobium oxide coating for orthopaedic applications

    Science.gov (United States)

    Pauline, S. Anne; Rajendran, N.

    2014-01-01

    Niobium oxide was synthesized by sol-gel methodology and a crystalline, nanoporous and adherent coating of Nb2O5 was deposited on 316L SS using the spin coating technique and heat treatment. The synthesis conditions were optimized to obtain a nanoporous morphology. The coating was characterized using attenuated total reflectance-Infrared spectroscopy (ATR-IR), X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX), atomic force microscopy (AFM) and transmission electron microscopy (TEM) and the formation of crystalline Nb2O5 coating with nanoporous morphology was confirmed. Mechanical studies confirmed that the coating has excellent adherence to the substrate and the hardness value of the coating was excellent. Contact angle analysis showed increased hydrophilicity for the coated substrate. In vitro bioactivity test confirmed that the Nb2O5 coating with nanoporous morphology facilitated the growth of hydroxyapatite (HAp). This was further confirmed by the solution analysis test where increased uptake of calcium and phosphorous ions from simulated body fluid (SBF) was observed. Electrochemical evaluation of the coating confirmed that the crystalline coating is insulative and protective in nature and offered excellent corrosion protection to 316L SS. Thus, this study confirmed that the nanoporous crystalline Nb2O5 coating conferred bioactivity and enhanced corrosion resistance on 316L SS.

  7. Biomimetic novel nanoporous niobium oxide coating for orthopaedic applications

    Energy Technology Data Exchange (ETDEWEB)

    Pauline, S. Anne; Rajendran, N., E-mail: nrajendran@annauniv.edu

    2014-01-30

    Niobium oxide was synthesized by sol–gel methodology and a crystalline, nanoporous and adherent coating of Nb{sub 2}O{sub 5} was deposited on 316L SS using the spin coating technique and heat treatment. The synthesis conditions were optimized to obtain a nanoporous morphology. The coating was characterized using attenuated total reflectance-Infrared spectroscopy (ATR-IR), X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX), atomic force microscopy (AFM) and transmission electron microscopy (TEM) and the formation of crystalline Nb{sub 2}O{sub 5} coating with nanoporous morphology was confirmed. Mechanical studies confirmed that the coating has excellent adherence to the substrate and the hardness value of the coating was excellent. Contact angle analysis showed increased hydrophilicity for the coated substrate. In vitro bioactivity test confirmed that the Nb{sub 2}O{sub 5} coating with nanoporous morphology facilitated the growth of hydroxyapatite (HAp). This was further confirmed by the solution analysis test where increased uptake of calcium and phosphorous ions from simulated body fluid (SBF) was observed. Electrochemical evaluation of the coating confirmed that the crystalline coating is insulative and protective in nature and offered excellent corrosion protection to 316L SS. Thus, this study confirmed that the nanoporous crystalline Nb{sub 2}O{sub 5} coating conferred bioactivity and enhanced corrosion resistance on 316L SS.

  8. Understanding focused ion beam guided anodic alumina nanopore development

    International Nuclear Information System (INIS)

    Chen Bo; Lu, Kathy; Tian Zhipeng

    2011-01-01

    Graphical abstract: Display Omitted Highlights: → We study the effect of FIB patterning on pore evolution during anodization. → FIB patterned concaves with 1.5 nm depth can effectively guide nanopore growth. → The edge effect of FIB guided patterns causes nanopores to bend. → Anodization window is enlarged to 50-80 V for 150 nm interpore distance hexagonal arrays. - Abstract: Focused ion beam (FIB) patterning in combination with anodization has shown great promise in creating unique pore patterns. This work is aimed to understand the effect of the FIB patterned sites in guiding anodized pore development. Highly ordered porous anodic alumina has been created with the guidance of FIB created patterns on electropolished aluminum followed by oxalic acid anodization. Shallow concaves created by the FIB with only 1.5 nm depth can effectively guide the growth of ordered nanopore patterns. With the guidance of the FIB pattern, the anodization rate is much faster and the nanopore growth direction bends at the boundary of the FIB patterned and un-patterned regions. FIB patterning also enlarges the anodization window; ordered nanopore arrays with 150 nm interpore distances can be produced under an applied potential from 50 V to 80 V. The fundamental understanding of these unique processes is discussed.

  9. Single molecule transistor based nanopore for the detection of nicotine

    Science.gov (United States)

    Ray, S. J.

    2014-12-01

    A nanopore based detection methodology was proposed and investigated for the detection of Nicotine. This technique uses a Single Molecular Transistor working as a nanopore operational in the Coulomb Blockade regime. When the Nicotine molecule is pulled through the nanopore area surrounded by the Source(S), Drain (D), and Gate electrodes, the charge stability diagram can detect the presence of the molecule and is unique for a specific molecular structure. Due to the weak coupling between the different electrodes which is set by the nanopore size, the molecular energy states stay almost unaffected by the electrostatic environment that can be realised from the charge stability diagram. Identification of different orientation and position of the Nicotine molecule within the nanopore area can be made from specific regions of overlap between different charge states on the stability diagram that could be used as an electronic fingerprint for detection. This method could be advantageous and useful to detect the presence of Nicotine in smoke which is usually performed using chemical chromatography techniques.

  10. Nanoporous Pirani sensor based on anodic aluminum oxide

    Science.gov (United States)

    Jeon, Gwang-Jae; Kim, Woo Young; Shim, Hyun Bin; Lee, Hee Chul

    2016-09-01

    A nanoporous Pirani sensor based on anodic aluminum oxide (AAO) is proposed, and the quantitative relationship between the performance of the sensor and the porosity of the AAO membrane is characterized with a theoretical model. The proposed Pirani sensor is composed of a metallic resistor on a suspended nanoporous membrane, which simultaneously serves as the sensing area and the supporting structure. The AAO membrane has numerous vertically-tufted nanopores, resulting in a lower measurable pressure limit due to both the increased effective sensing area and the decreased effective thermal loss through the supporting structure. Additionally, the suspended AAO membrane structure, with its outer periphery anchored to the substrate, known as a closed-type design, is demonstrated using nanopores of AAO as an etch hole without a bulk micromachining process used on the substrate. In a CMOS-compatible process, a 200 μm × 200 μm nanoporous Pirani sensor with porosity of 25% was capable of measuring the pressure from 0.1 mTorr to 760 Torr. With adjustment of the porosity of the AAO, the measurable range could be extended toward lower pressures of more than one decade compared to a non-porous membrane with an identical footprint.

  11. Antibacterial hemostatic dressings with nanoporous bioglass containing silver

    Directory of Open Access Journals (Sweden)

    Hu G

    2012-05-01

    Full Text Available Gangfeng Hu,1 Luwei Xiao,2 Peijian Tong,2 Dawei Bi,1 Hui Wang,1 Haitao Ma,1 Gang Zhu,1 Hui Liu21The First People’s Hospital of Xiaoshan, Hangzhou, China; 2Zhejiang Traditional Chinese Medical University, Hangzhou, ChinaAbstract: Nanoporous bioglass containing silver (n-BGS was fabricated using the sol-gel method, with cetyltrimethyl ammonium bromide as template. The results showed that n-BGS with nanoporous structure had a surface area of 467 m2/g and a pore size of around 6 nm, and exhibited a significantly higher water absorption rate compared with BGS without nanopores. The n-BGS containing small amounts of silver (Ag had a slight effect on its surface area. The n-BGS containing 0.02 wt% Ag, without cytotoxicity, had a good antibacterial effect on Escherichia coli, and its antibacterial rate reached 99% in 12 hours. The n-BGS’s clotting ability significantly decreased prothrombin time (PT and activated partial thromboplastin time (APTT, indicating n-BGS with a higher surface area could significantly promote blood clotting (by decreasing clotting time compared with BGS without nanopores. Effective hemostasis was achieved in skin injury models, and bleeding time was reduced. It is suggested that n-BGS could be a good dressing, with antibacterial and hemostatic properties, which might shorten wound bleeding time and control hemorrhage.Keywords: antibacterial, bioglass, cytotoxicity, dressing, hemostasis, nanopore, silver

  12. Vapor nucleation paths in lyophobic nanopores.

    Science.gov (United States)

    Tinti, Antonio; Giacomello, Alberto; Casciola, Carlo Massimo

    2018-04-19

    In recent years, technologies revolving around the use of lyophobic nanopores gained considerable attention in both fundamental and applied research. Owing to the enormous internal surface area, heterogeneous lyophobic systems (HLS), constituted by a nanoporous lyophobic material and a non-wetting liquid, are promising candidates for the efficient storage or dissipation of mechanical energy. These diverse applications both rely on the forced intrusion and extrusion of the non-wetting liquid inside the pores; the behavior of HLS for storage or dissipation depends on the hysteresis between these two processes, which, in turn, are determined by the microscopic details of the system. It is easy to understand that molecular simulations provide an unmatched tool for understanding phenomena at these scales. In this contribution we use advanced atomistic simulation techniques in order to study the nucleation of vapor bubbles inside lyophobic mesopores. The use of the string method in collective variables allows us to overcome the computational challenges associated with the activated nature of the phenomenon, rendering a detailed picture of nucleation in confinement. In particular, this rare event method efficiently searches for the most probable nucleation path(s) in otherwise intractable, high-dimensional free-energy landscapes. Results reveal the existence of several independent nucleation paths associated with different free-energy barriers. In particular, there is a family of asymmetric transition paths, in which a bubble forms at one of the walls; the other family involves the formation of axisymmetric bubbles with an annulus shape. The computed free-energy profiles reveal that the asymmetric path is significantly more probable than the symmetric one, while the exact position where the asymmetric bubble forms is less relevant for the free energetics of the process. A comparison of the atomistic results with continuum models is also presented, showing how, for simple

  13. Synthesis of ordered large-scale ZnO nanopore arrays

    International Nuclear Information System (INIS)

    Ding, G.Q.; Shen, W.Z.; Zheng, M.J.; Fan, D.H.

    2006-01-01

    An effective approach is demonstrated for growing ordered large-scale ZnO nanopore arrays through radio-frequency magnetron sputtering deposition on porous alumina membranes (PAMs). The realization of highly ordered hexagonal ZnO nanopore arrays benefits from the unique properties of ZnO (hexagonal structure, polar surfaces, and preferable growth directions) and PAMs (controllable hexagonal nanopores and localized negative charges). Further evidence has been shown through the effects of nanorod size and thermal treatment of PAMs on the yielded morphology of ZnO nanopore arrays. This approach opens the possibility of creating regular semiconducting nanopore arrays for the application of filters, sensors, and templates

  14. Porous silicon damage enhanced phosphorus and aluminium gettering of p-type Czochralski silicon

    International Nuclear Information System (INIS)

    Hassen, M.; Ben Jaballah, A.; Hajji, M.; Rahmouni, H.; Selmi, A.; Ezzaouia, H.

    2005-01-01

    In this work, porous silicon damage (PSD) is presented as a simple sequence for efficient external purification techniques. The method consists of using thin nanoporous p-type silicon on both sides of the silicon substrates with randomly hemispherical voids. Then, two main sample types are processed. In the first type, thin aluminium layers (≥1 μm) are thermally evaporated followed by photo-thermal annealing treatments in N 2 atmosphere at one of several temperatures ranging between 600 and 800 deg. C. In the second type, phosphorus is continually diffused in N 2 /O 2 ambient in a solid phase from POCl 3 solution during heating at one of several temperatures ranging between 750 and 1000 deg. C for 1 h. Hall Effect and Van Der Pauw methods prove the existence of an optimum temperature in the case of phosphorus gettering at 900 deg. C yielding a Hall mobility of about 982 cm 2 V -1 s -1 . However, in the case of aluminium gettering, there is no gettering limit in the as mentioned temperature range. Metal/Si Schottky diodes are elaborated to clarify these improvements. In this study, we demonstrate that enhanced metal solubility model cannot explain the gettering effect. The solid solubility of aluminium is higher than that of P atoms in silicon; however, the device yield confirms the effectiveness of phosphorus as compared to aluminium

  15. Enzyme specific activity in functionalized nanoporous supports

    International Nuclear Information System (INIS)

    Lei Chenghong; Soares, Thereza A; Shin, Yongsoon; Liu Jun; Ackerman, Eric J

    2008-01-01

    Here we reveal that enzyme specific activity can be increased substantially by changing the protein loading density (P LD ) in functionalized nanoporous supports so that the enzyme immobilization efficiency (I e , defined as the ratio of the specific activity of the immobilized enzyme to the specific activity of the free enzyme in solution) can be much higher than 100%. A net negatively charged glucose oxidase (GOX) and a net positively charged organophosphorus hydrolase (OPH) were entrapped spontaneously in NH 2 - and HOOC-functionalized mesoporous silica (300 A, FMS) respectively. The specific activity of GOX entrapped in FMS increased with decreasing P LD . With decreasing P LD , I e of GOX in FMS increased from 150%. Unlike GOX, OPH in HOOC-FMS showed increased specific activity with increasing P LD . With increasing P LD , the corresponding I e of OPH in FMS increased from 100% to>200%. A protein structure-based analysis of the protein surface charges directing the electrostatic interaction-based orientation of the protein molecules in FMS demonstrates that substrate access to GOX molecules in FMS is limited at high P LD , consequently lowering the GOX specific activity. In contrast, substrate access to OPH molecules in FMS remains open at high P LD and may promote a more favorable confinement environment that enhances the OPH activity

  16. Phonon bottleneck identification in disordered nanoporous materials

    Science.gov (United States)

    Romano, Giuseppe; Grossman, Jeffrey C.

    2017-09-01

    Nanoporous materials are a promising platform for thermoelectrics in that they offer high thermal conductivity tunability while preserving good electrical properties, a crucial requirement for high-efficiency thermal energy conversion. Understanding the impact of the pore arrangement on thermal transport is pivotal to engineering realistic materials, where pore disorder is unavoidable. Although there has been considerable progress in modeling thermal size effects in nanostructures, it has remained a challenge to screen such materials over a large phase space due to the slow simulation time required for accurate results. We use density functional theory in connection with the Boltzmann transport equation to perform calculations of thermal conductivity in disordered porous materials. By leveraging graph theory and regressive analysis, we identify the set of pores representing the phonon bottleneck and obtain a descriptor for thermal transport, based on the sum of the pore-pore distances between such pores. This approach provide a simple tool to estimate phonon suppression in realistic porous materials for thermoelectric applications and enhance our understanding of heat transport in disordered materials.

  17. Environmental Green Chemistry Applications of Nanoporous Carbons

    Energy Technology Data Exchange (ETDEWEB)

    Matos, J.; Garcia, A; Poon, P

    2010-01-01

    Influence of surface properties of nanoporous carbons on activity and selectivity during the photooxidation of 4-chlorophenol on UV-irradiated TiO{sub 2} was performed. Characterization by infrared spectroscopy, X-ray photoelectronic spectroscopy and X-ray absorption near edge structure spectroscopy confirm the presence of a contact interface between both solids and suggest the coordination of some functional organic groups of the carbon surface, mainly ethers and carboxylic acids, to metallic centre Ti{sup +4} in TiO{sub 2}. Changes in surface pH of carbons from basic to neutral or acid remarkably increase the production of 4-chlorocathecol by a factor of 22 on TiO{sub 2}-Carbon in comparison of TiO{sub 2} alone. A scheme of interaction between TiO{sub 2} and carbon is proposed to the increased photoactivity of TiO{sub 2} and a reaction mechanism for the different intermediate products detected is also proposed. Results showed that TiO{sub 2}-Carbon can be used as an alternative photocatalyst for environmental green chemistry and selective organic synthesis applications.

  18. Nanoporous Au: an unsupported pure gold catalyst?

    Energy Technology Data Exchange (ETDEWEB)

    Wittstock, A; Neumann, B; Schaefer, A; Dumbuya, K; Kuebel, C; Biener, M; Zielasek, V; Steinrueck, H; Gottfried, M; Biener, J; Hamza, A; B?umer, M

    2008-09-04

    The unique properties of gold especially in low temperature CO oxidation have been ascribed to a combination of various effects. In particular, particle sizes below a few nm and specific particle-support interactions have been shown to play important roles. On the contrary, recent reports revealed that monolithic nanoporous gold (npAu) prepared by leaching a less noble metal, such as Ag, out of the corresponding alloy can also exhibit remarkably high catalytic activity for CO oxidation, even though no support is present. Therefore, it was claimed to be a pure and unsupported gold catalyst. We investigated npAu with respect to its morphology, surface composition and catalytic properties. In particular, we studied the reaction kinetics for low temperature CO oxidation in detail taking mass transport limitation due to the porous structure of the material into account. Our results reveal that Ag, even if removed almost completely from the bulk, segregates to the surface resulting in surface concentrations of up to 10 at%. Our data suggest that this Ag plays a significant role in activation of molecular oxygen. Therefore, npAu should be considered as a bimetallic catalyst rather than a pure Au catalyst.

  19. On site DNA barcoding by nanopore sequencing.

    Directory of Open Access Journals (Sweden)

    Michele Menegon

    Full Text Available Biodiversity research is becoming increasingly dependent on genomics, which allows the unprecedented digitization and understanding of the planet's biological heritage. The use of genetic markers i.e. DNA barcoding, has proved to be a powerful tool in species identification. However, full exploitation of this approach is hampered by the high sequencing costs and the absence of equipped facilities in biodiversity-rich countries. In the present work, we developed a portable sequencing laboratory based on the portable DNA sequencer from Oxford Nanopore Technologies, the MinION. Complementary laboratory equipment and reagents were selected to be used in remote and tough environmental conditions. The performance of the MinION sequencer and the portable laboratory was tested for DNA barcoding in a mimicking tropical environment, as well as in a remote rainforest of Tanzania lacking electricity. Despite the relatively high sequencing error-rate of the MinION, the development of a suitable pipeline for data analysis allowed the accurate identification of different species of vertebrates including amphibians, reptiles and mammals. In situ sequencing of a wild frog allowed us to rapidly identify the species captured, thus confirming that effective DNA barcoding in the field is possible. These results open new perspectives for real-time-on-site DNA sequencing thus potentially increasing opportunities for the understanding of biodiversity in areas lacking conventional laboratory facilities.

  20. Noise and its reduction in graphene based nanopore devices

    International Nuclear Information System (INIS)

    Kumar, Ashvani; Park, Kyeong-Beom; Kim, Hyun-Mi; Kim, Ki-Bum

    2013-01-01

    Ionic current fluctuations in graphene nanopore devices are a ubiquitous phenomenon and are responsible for degraded spatial and temporal resolution. Here, we descriptively investigate the impact of different substrate materials (Si and quartz) and membrane thicknesses on noise characteristics of graphene nanopore devices. To mitigate the membrane fluctuations and pin-hole defects, a SiN x membrane is transferred onto the substrate and a pore of approximately 70 nm in diameter is perforated prior to the graphene transfer. Comprehensive noise study reveals that the few layer graphene transferred onto the quartz substrate possesses low noise level and higher signal to noise ratio as compared to single layer graphene, without deteriorating the spatial resolution. The findings here point to improvement of graphene based nanopore devices for exciting opportunities in future single-molecule genomic screening devices. (paper)

  1. Protein sequencing via nanopore based devices: a nanofluidics perspective

    Science.gov (United States)

    Chinappi, Mauro; Cecconi, Fabio

    2018-05-01

    Proteins perform a huge number of central functions in living organisms, thus all the new techniques allowing their precise, fast and accurate characterization at single-molecule level certainly represent a burst in proteomics with important biomedical impact. In this review, we describe the recent progresses in the developing of nanopore based devices for protein sequencing. We start with a critical analysis of the main technical requirements for nanopore protein sequencing, summarizing some ideas and methodologies that have recently appeared in the literature. In the last sections, we focus on the physical modelling of the transport phenomena occurring in nanopore based devices. The multiscale nature of the problem is discussed and, in this respect, some of the main possible computational approaches are illustrated.

  2. Detection of DNA hybridizations using solid-state nanopores

    International Nuclear Information System (INIS)

    Balagurusamy, Venkat S K; Weinger, Paul; Sean Ling, Xinsheng

    2010-01-01

    We report an experimental study of using DNA translocation through solid-state nanopores to detect the sequential arrangement of two double-stranded 12-mer hybridization segments on a single-stranded DNA molecule. The sample DNA is a trimer molecule formed by hybridizing three single-stranded oligonucleotides. A polystyrene bead is attached to the end of the trimer DNA, providing a mechanism in slowing down the translocation and suppressing the thermal diffusion, thereby allowing the detection of short features of DNA by standard patch-clamp electronics. The electrical signature of the translocation of a trimer molecule through a nanopore has been identified successfully in the temporal traces of ionic current. The results reported here represent the first successful attempt in using a solid-state nanopore as an ionic scanning device in resolving individual hybridization segments (or 'probes') on a DNA molecule.

  3. Detection of DNA hybridizations using solid-state nanopores

    Energy Technology Data Exchange (ETDEWEB)

    Balagurusamy, Venkat S K; Weinger, Paul; Sean Ling, Xinsheng, E-mail: Xinsheng_Ling@brown.edu [Department of Physics, Brown University, Providence, RI 02912 (United States)

    2010-08-20

    We report an experimental study of using DNA translocation through solid-state nanopores to detect the sequential arrangement of two double-stranded 12-mer hybridization segments on a single-stranded DNA molecule. The sample DNA is a trimer molecule formed by hybridizing three single-stranded oligonucleotides. A polystyrene bead is attached to the end of the trimer DNA, providing a mechanism in slowing down the translocation and suppressing the thermal diffusion, thereby allowing the detection of short features of DNA by standard patch-clamp electronics. The electrical signature of the translocation of a trimer molecule through a nanopore has been identified successfully in the temporal traces of ionic current. The results reported here represent the first successful attempt in using a solid-state nanopore as an ionic scanning device in resolving individual hybridization segments (or 'probes') on a DNA molecule.

  4. Detecting and identifying small molecules in a nanopore flux capacitor

    International Nuclear Information System (INIS)

    Bearden, Samuel; Zhang, Guigen; McClure, Ethan

    2016-01-01

    A new method of molecular detection in a metallic-semiconductor nanopore was developed and evaluated with experimental and computational methods. Measurements were made of the charging potential of the electrical double layer (EDL) capacitance as charge-carrying small molecules translocated the nanopore. Signals in the charging potential were found to be correlated to the physical properties of analyte molecules. From the measured signals, we were able to distinguish molecules with different valence charge or similar valence charge but different size. The relative magnitude of the signals from different analytes was consistent over a wide range of experimental conditions, suggesting that the detected signals are likely due to single molecules. Computational modeling of the nanopore system indicated that the double layer potential signal may be described in terms of disruption of the EDL structure due to the size and charge of the analyte molecule, in agreement with Huckel and Debye’s analysis of the electrical atmosphere of electrolyte solutions. (paper)

  5. Capillary condensation and evaporation in alumina nanopores with controlled modulations.

    Science.gov (United States)

    Bruschi, Lorenzo; Mistura, Giampaolo; Liu, Lifeng; Lee, Woo; Gösele, Ulrich; Coasne, Benoit

    2010-07-20

    Capillary condensation in nanoporous anodic aluminum oxide presenting not interconnected pores with controlled modulations is studied using adsorption experiments and molecular simulations. Both the experimental and simulation data show that capillary condensation and evaporation are driven by the smallest size of the nanopore (constriction). The adsorption isotherms for the open and closed pores are almost identical if constrictions are added to the system. The latter result implies that the type of pore ending does not matter in modulated pores. Thus, the presence of hysteresis loops observed in adsorption isotherms measured in straight nanopores with closed bottom ends can be explained in terms of geometrical inhomogeneities along the pore axis. More generally, these results provide a general picture of capillary condensation and evaporation in constricted or modulated pores that can be used for the interpretation of adsorption in disordered porous materials.

  6. Nanoporous cerium oxide thin film for glucose biosensor.

    Science.gov (United States)

    Saha, Shibu; Arya, Sunil K; Singh, S P; Sreenivas, K; Malhotra, B D; Gupta, Vinay

    2009-03-15

    Nanoporous cerium oxide (CeO(2)) thin film deposited onto platinum (Pt) coated glass plate using pulsed laser deposition (PLD) has been utilized for immobilization of glucose oxidase (GOx). Atomic force microscopy studies reveal the formation of nanoporous surface morphology of CeO(2) thin film. Response studies carried out using differential pulsed voltammetry (DPV) and optical measurements show that the GOx/CeO(2)/Pt bio-electrode shows linearity in the range of 25-300 mg/dl of glucose concentration. The low value of Michaelis-Menten constant (1.01 mM) indicates enhanced enzyme affinity of GOx to glucose. The observed results show promising application of the nanoporous CeO(2) thin film for glucose sensing application without any surface functionalization or mediator.

  7. Multistep Current Signal in Protein Translocation through Graphene Nanopores

    KAUST Repository

    Bonome, Emma Letizia

    2015-05-07

    © 2015 American Chemical Society. In nanopore sensing experiments, the properties of molecules are probed by the variation of ionic currents flowing through the nanopore. In this context, the electronic properties and the single-layer thickness of graphene constitute a major advantage for molecule characterization. Here we analyze the translocation pathway of the thioredoxin protein across a graphene nanopore, and the related ionic currents, by integrating two nonequilibrium molecular dynamics methods with a bioinformatic structural analysis. To obtain a qualitative picture of the translocation process and to identify salient features we performed unsupervised structural clustering on translocation conformations. This allowed us to identify some specific and robust translocation intermediates, characterized by significantly different ionic current flows. We found that the ion current strictly anticorrelates with the amount of pore occupancy by thioredoxin residues, providing a putative explanation of the multilevel current scenario observed in recently published translocation experiments.

  8. Transport behavior of water molecules through two-dimensional nanopores

    International Nuclear Information System (INIS)

    Zhu, Chongqin; Li, Hui; Meng, Sheng

    2014-01-01

    Water transport through a two-dimensional nanoporous membrane has attracted increasing attention in recent years thanks to great demands in water purification and desalination applications. However, few studies have been reported on the microscopic mechanisms of water transport through structured nanopores, especially at the atomistic scale. Here we investigate the microstructure of water flow through two-dimensional model graphene membrane containing a variety of nanopores of different size by using molecular dynamics simulations. Our results clearly indicate that the continuum flow transits to discrete molecular flow patterns with decreasing pore sizes. While for pores with a diameter ≥15 Å water flux exhibits a linear dependence on the pore area, a nonlinear relationship between water flux and pore area has been identified for smaller pores. We attribute this deviation from linear behavior to the presence of discrete water flow, which is strongly influenced by the water-membrane interaction and hydrogen bonding between water molecules

  9. Nanopore wall-liquid interaction under scope of molecular dynamics study: Review

    Science.gov (United States)

    Tsukanov, A. A.; Psakhie, S. G.

    2017-12-01

    The present review is devoted to the analysis of recent molecular dynamics based on the numerical studies of molecular aspects of solid-fluid interaction in nanoscale channels. Nanopore wall-liquid interaction plays the crucial role in such processes as gas separation, water desalination, liquids decontamination, hydrocarbons and water transport in nano-fractured geological formations. Molecular dynamics simulation is one of the most suitable tools to study molecular level effects occurred in such multicomponent systems. The nanopores are classified by their geometry to four groups: nanopore in nanosheet, nanotube-like pore, slit-shaped nanopore and soft-matter nanopore. The review is focused on the functionalized nanopores in boron nitride nanosheets as novel selective membranes and on the slit-shaped nanopores formed by minerals.

  10. Influence of nanopore surface charge and magnesium ion on polyadenosine translocation

    International Nuclear Information System (INIS)

    Lepoitevin, Mathilde; Bechelany, Mikhael; Janot, Jean-Marc; Balme, Sebastien; Coulon, Pierre Eugène; Cambedouzou, Julien

    2015-01-01

    We investigate the influence of a nanopore surface state and the addition of Mg 2+ on poly-adenosine translocation. To do so, two kinds of nanopores with a low aspect ratio (diameter ∼3–5 nm, length 30 nm) were tailored: the first one with a negative charge surface and the second one uncharged. It was shown that the velocity and the energy barrier strongly depend on the nanopore surface. Typically if the nanopore and polyA exhibit a similar charge, the macromolecule velocity increases and its global energy barrier of entrance in the nanopore decreases, as opposed to the non-charged nanopore. Moreover, the addition of a divalent chelating cation induces an increase of energy barrier of entrance, as expected. However, for a negative nanopore, this effect is counterbalanced by the inversion of the surface charge induced by the adsorption of divalent cations. (paper)

  11. Nanopore Electrochemistry: A Nexus for Molecular Control of Electron Transfer Reactions

    Science.gov (United States)

    2018-01-01

    Pore-based structures occur widely in living organisms. Ion channels embedded in cell membranes, for example, provide pathways, where electron and proton transfer are coupled to the exchange of vital molecules. Learning from mother nature, a recent surge in activity has focused on artificial nanopore architectures to effect electrochemical transformations not accessible in larger structures. Here, we highlight these exciting advances. Starting with a brief overview of nanopore electrodes, including the early history and development of nanopore sensing based on nanopore-confined electrochemistry, we address the core concepts and special characteristics of nanopores in electron transfer. We describe nanopore-based electrochemical sensing and processing, discuss performance limits and challenges, and conclude with an outlook for next-generation nanopore electrode sensing platforms and the opportunities they present. PMID:29392173

  12. Nanopore Electrochemistry: A Nexus for Molecular Control of Electron Transfer Reactions

    Directory of Open Access Journals (Sweden)

    Kaiyu Fu

    2018-01-01

    Full Text Available Pore-based structures occur widely in living organisms. Ion channels embedded in cell membranes, for example, provide pathways, where electron and proton transfer are coupled to the exchange of vital molecules. Learning from mother nature, a recent surge in activity has focused on artificial nanopore architectures to effect electrochemical transformations not accessible in larger structures. Here, we highlight these exciting advances. Starting with a brief overview of nanopore electrodes, including the early history and development of nanopore sensing based on nanopore-confined electrochemistry, we address the core concepts and special characteristics of nanopores in electron transfer. We describe nanopore-based electrochemical sensing and processing, discuss performance limits and challenges, and conclude with an outlook for next-generation nanopore electrode sensing platforms and the opportunities they present.

  13. Coarsening by network restructuring in model nanoporous gold

    International Nuclear Information System (INIS)

    Kolluri, Kedarnath; Demkowicz, Michael J.

    2011-01-01

    Using atomistic modeling, we show that restructuring of the network of interconnected ligaments causes coarsening in a model of nanoporous gold. The restructuring arises from the collapse of some ligaments onto neighboring ones and is enabled by localized plasticity at ligaments and nodes. This mechanism may explain the occurrence of enclosed voids and reduction in volume in nanoporous metals during their synthesis. An expression is developed for the critical ligament radius below which coarsening by network restructuring may occur spontaneously, setting a lower limit to the ligament dimensions of nanofoams.

  14. Nanoporous zinc oxide films prepared by magnetron sputtering

    International Nuclear Information System (INIS)

    Ghimpu, L.; Lupan, O.; Popescu, L.; Tiginyanu, I.M.

    2011-01-01

    In this paper we demonstrate an inexpensive approach for the fabrication of nanoporous zinc oxide films by using magnetron sputtering. Study of the structural properties proves the crystallographic perfection of porous nanostructures and the possibility of its controlling by adjusting the technological parameters in the growth process. The XRD pattern of nanoporous ZnO films exhibits high intensity of the peaks relative to the background signal which is indicative of the ZnO hexagonal phase and a good crystallinity of the samples grown by magnetron sputtering.

  15. Active sieving across driven nanopores for tunable selectivity

    Science.gov (United States)

    Marbach, Sophie; Bocquet, Lydéric

    2017-10-01

    Molecular separation traditionally relies on sieving processes across passive nanoporous membranes. Here we explore theoretically the concept of non-equilibrium active sieving. We investigate a simple model for an active noisy nanopore, where gating—in terms of size or charge—is externally driven at a tunable frequency. Our analytical and numerical results unveil a rich sieving diagram in terms of the forced gating frequency. Unexpectedly, the separation ability is strongly increased as compared to its passive (zero frequency) counterpart. It also points to the possibility of tuning dynamically the osmotic pressure. Active separation outperforms passive sieving and represents a promising avenue for advanced filtration.

  16. Discriminating Bacteria with Optical Sensors Based on Functionalized Nanoporous Xerogels

    Directory of Open Access Journals (Sweden)

    Sabine Crunaire

    2014-06-01

    Full Text Available An innovative and low-cost method is proposed for the detection and discrimination of indole-positive pathogen bacteria. The method allows the non-invasive detection of gaseous indole, released by bacteria, with nanoporous colorimetric sensors. The innovation comes from the use of nanoporous matrices doped with 4-(dimethylamino-cinnamaldehyde, which act as sponges to trap and concentrate the targeted analyte and turn from transparent to dark green, long before the colonies get visible with naked eyes. With such sensors, it was possible to discriminate E. coli from H. alvei, two indole-positive and negative bacteria after seven hours of incubation.

  17. Human aortic endothelial cell morphology influenced by topography of porous silicon substrates.

    Science.gov (United States)

    Formentín, Pilar; Catalán, Úrsula; Fernández-Castillejo, Sara; Alba, Maria; Baranowska, Malgorzata; Solà, Rosa; Pallarès, Josep; Marsal, Lluís F

    2015-10-01

    Porous silicon has received much attention because of its optical properties and for its usefulness in cell-based biosensing, drug delivery, and tissue engineering applications. Surface properties of the biomaterial are associated with cell adhesion and with proliferation, migration, and differentiation. The present article analyzes the behavior of human aortic endothelial cells in macro- and nanoporous collagen-modified porous silicon samples. On both substrates, cells are well adhered and numerous. Confocal microscopy and scanning electron microscopy were employed to study the effects of porosity on the morphology of the cells. On macroporous silicon, filopodia is not observed but the cell spreads on the surface, increasing the lamellipodia surface which penetrates the macropore. On nanoporous silicon, multiple filopodia were found to branch out from the cell body. These results demonstrate that the pore size plays a key role in controlling the morphology and growth rate of human aortic endothelial cells, and that these forms of silicon can be used to control cell development in tissue engineering as well as in basic cell biology research. © The Author(s) 2015.

  18. Electrodeposition at room temperature of amorphous silicon and germanium nanowires in ionic liquid

    Energy Technology Data Exchange (ETDEWEB)

    Martineau, F; Namur, K; Mallet, J; Delavoie, F; Troyon, M; Molinari, M [Laboratoire de Microscopies et d' Etude de Nanostructures (LMEN EA3799), Universite de Reims Champagne Ardennes (URCA), Reims Cedex 2 (France); Endres, F, E-mail: michael.molinari@univ-reims.fr [Institute of Particle Technology, Chair of Interface Processes, Clausthal University of Technology, D-36678 Clausthal-Zellerfeld (Germany)

    2009-11-15

    The electrodeposition at room temperature of silicon and germanium nanowires from the air- and water-stable ionic liquid 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (P{sub 1,4}) containing SiCl{sub 4} as Si source or GeCl{sub 4} as Ge source is investigated by cyclic voltammetry. By using nanoporous polycarbonate membranes as templates, it is possible to reproducibly grow pure silicon and germanium nanowires of different diameters. The nanowires are composed of pure amorphous silicon or germanium. The nanowires have homogeneous cylindrical shape with a roughness of a few nanometres on the wire surfaces. The nanowires' diameters and lengths well match with the initial membrane characteristics. Preliminary photoluminescence experiments exhibit strong emission in the near infrared for the amorphous silicon nanowires.

  19. Electrochromic artificial muscles based on nanoporous metal-polymer composites

    NARCIS (Netherlands)

    Detsi, E.; Onck, P. R.; De Hosson, J. T. M.

    2013-01-01

    This work shows that a nano-coating of electrochromic polymer grown onto the ligaments of nanoporous gold causes reversible dimensional and color changes during electrochemical actuation. This combination of electromechanical and optical properties opens additional avenues for the applications of

  20. Nanopore Sequencing as a Rapidly Deployable Ebola Outbreak Tool.

    Science.gov (United States)

    Hoenen, Thomas; Groseth, Allison; Rosenke, Kyle; Fischer, Robert J; Hoenen, Andreas; Judson, Seth D; Martellaro, Cynthia; Falzarano, Darryl; Marzi, Andrea; Squires, R Burke; Wollenberg, Kurt R; de Wit, Emmie; Prescott, Joseph; Safronetz, David; van Doremalen, Neeltje; Bushmaker, Trenton; Feldmann, Friederike; McNally, Kristin; Bolay, Fatorma K; Fields, Barry; Sealy, Tara; Rayfield, Mark; Nichol, Stuart T; Zoon, Kathryn C; Massaquoi, Moses; Munster, Vincent J; Feldmann, Heinz

    2016-02-01

    Rapid sequencing of RNA/DNA from pathogen samples obtained during disease outbreaks provides critical scientific and public health information. However, challenges exist for exporting samples to laboratories or establishing conventional sequencers in remote outbreak regions. We successfully used a novel, pocket-sized nanopore sequencer at a field diagnostic laboratory in Liberia during the current Ebola virus outbreak.

  1. Nanoporous gold assembly of glucose oxidase for electrochemical biosensing

    DEFF Research Database (Denmark)

    Xiao, Xinxin; Ulstrup, Jens; Li, Hui

    2014-01-01

    Nanoporous gold (NPG) is composed of three-dimensional (3D) bicontinuous nanostructures with large surface area. Nano-channels inside NPG provide an ideal local environment for immobilization of enzyme molecules with expected stabilization of the protein molecules. In this work, glucose oxidase (...

  2. Hydrogen storage in nanoporous carbon materials: myth and facts.

    Science.gov (United States)

    Kowalczyk, Piotr; Hołyst, Robert; Terrones, Mauricio; Terrones, Humberto

    2007-04-21

    We used Grand canonical Monte Carlo simulation to model the hydrogen storage in the primitive, gyroid, diamond, and quasi-periodic icosahedral nanoporous carbon materials and in carbon nanotubes. We found that none of the investigated nanoporous carbon materials satisfy the US Department of Energy goal of volumetric density and mass storage for automotive application (6 wt% and 45 kg H(2) m(-3)) at considered storage condition. Our calculations indicate that quasi-periodic icosahedral nanoporous carbon material can reach the 6 wt% at 3.8 MPa and 77 K, but the volumetric density does not exceed 24 kg H(2) m(-3). The bundle of single-walled carbon nanotubes can store only up to 4.5 wt%, but with high volumetric density of 42 kg H(2) m(-3). All investigated nanoporous carbon materials are not effective against compression above 20 MPa at 77 K because the adsorbed density approaches the density of the bulk fluid. It follows from this work that geometry of carbon surfaces can enhance the storage capacity only to a limited extent. Only a combination of the most effective structure with appropriate additives (metals) can provide an efficient storage medium for hydrogen in the quest for a source of "clean" energy.

  3. Liquid Core Waveguides by UV Modification of Nanoporous Polymer

    DEFF Research Database (Denmark)

    Christiansen, Mads Brøkner; Gopalakrishnan, Nimi; Sagar, Kaushal Shashikant

    2011-01-01

    Liquid core waveguides are fabricated from a self-assembled nanoporous polymer, with a porosity of 40%. The high porosity results in an effective refractive index of 1.26 for visible light, i.e. below the refractive index of aqueous solutions. However, since the polymer is hydrophobic, fluids...

  4. Mechanical stability of nanoporous metals with small ligament sizes

    International Nuclear Information System (INIS)

    Crowson, Douglas A.; Farkas, Diana; Corcoran, Sean G.

    2009-01-01

    Digital samples of nanoporous gold with small ligament sizes were studied by atomistic simulation using different interatomic potentials that represent varying surface stress values. We predict a surface relaxation driven mechanical instability for these materials. Plastic deformation is induced by the surface stress without external load, related to the combination of the surface stress value and the surface to volume ratio.

  5. Gate modulation of proton transport in a nanopore.

    Science.gov (United States)

    Mei, Lanju; Yeh, Li-Hsien; Qian, Shizhi

    2016-03-14

    Proton transport in confined spaces plays a crucial role in many biological processes as well as in modern technological applications, such as fuel cells. To achieve active control of proton conductance, we investigate for the first time the gate modulation of proton transport in a pH-regulated nanopore by a multi-ion model. The model takes into account surface protonation/deprotonation reactions, surface curvature, electroosmotic flow, Stern layer, and electric double layer overlap. The proposed model is validated by good agreement with the existing experimental data on nanopore conductance with and without a gate voltage. The results show that the modulation of proton transport in a nanopore depends on the concentration of the background salt and solution pH. Without background salt, the gated nanopore exhibits an interesting ambipolar conductance behavior when pH is close to the isoelectric point of the dielectric pore material, and the net ionic and proton conductance can be actively regulated with a gate voltage as low as 1 V. The higher the background salt concentration, the lower is the performance of the gate control on the proton transport.

  6. Solid-state nanopores for probing DNA and protein

    NARCIS (Netherlands)

    Plesa, C.

    2015-01-01

    Solid-state nanopores are small nanometer-scale holes in thin membranes. When used to separate two chambers containing salt solution, any biomolecule passing from one chamber to the other is forced to pass through the pore constriction. An electric field applied across the membrane is used to create

  7. Fine-tuning the feature size of nanoporous silver

    NARCIS (Netherlands)

    Detsi, Eric; Vukovic, Zorica; Punzhin, Sergey; Bronsveld, Paul M.; Onck, Patrick R.; De Hosson, Jeff Th M.

    2012-01-01

    We show that the characteristic ligament size of nanoporous Ag synthesized by chemical dissolution of Al from Ag-Al alloys can be tuned from the current submicrometer size (similar to 100-500 nm) down to a much smaller length scale (similar to 30-60 nm). This is achieved by suppressing the formation

  8. Ion transport in sub-5-nm graphene nanopores

    International Nuclear Information System (INIS)

    Suk, Myung E.; Aluru, N. R.

    2014-01-01

    Graphene nanopore is a promising device for single molecule sensing, including DNA bases, as its single atom thickness provides high spatial resolution. To attain high sensitivity, the size of the molecule should be comparable to the pore diameter. However, when the pore diameter approaches the size of the molecule, ion properties and dynamics may deviate from the bulk values and continuum analysis may not be accurate. In this paper, we investigate the static and dynamic properties of ions with and without an external voltage drop in sub-5-nm graphene nanopores using molecular dynamics simulations. Ion concentration in graphene nanopores sharply drops from the bulk concentration when the pore radius is smaller than 0.9 nm. Ion mobility in the pore is also smaller than bulk ion mobility due to the layered liquid structure in the pore-axial direction. Our results show that a continuum analysis can be appropriate when the pore radius is larger than 0.9 nm if pore conductivity is properly defined. Since many applications of graphene nanopores, such as DNA and protein sensing, involve ion transport, the results presented here will be useful not only in understanding the behavior of ion transport but also in designing bio-molecular sensors

  9. Warming up human body by nanoporous metallized polyethylene textile.

    Science.gov (United States)

    Cai, Lili; Song, Alex Y; Wu, Peilin; Hsu, Po-Chun; Peng, Yucan; Chen, Jun; Liu, Chong; Catrysse, Peter B; Liu, Yayuan; Yang, Ankun; Zhou, Chenxing; Zhou, Chenyu; Fan, Shanhui; Cui, Yi

    2017-09-19

    Space heating accounts for the largest energy end-use of buildings that imposes significant burden on the society. The energy wasted for heating the empty space of the entire building can be saved by passively heating the immediate environment around the human body. Here, we demonstrate a nanophotonic structure textile with tailored infrared (IR) property for passive personal heating using nanoporous metallized polyethylene. By constructing an IR-reflective layer on an IR-transparent layer with embedded nanopores, the nanoporous metallized polyethylene textile achieves a minimal IR emissivity (10.1%) on the outer surface that effectively suppresses heat radiation loss without sacrificing wearing comfort. This enables 7.1 °C decrease of the set-point compared to normal textile, greatly outperforming other radiative heating textiles by more than 3 °C. This large set-point expansion can save more than 35% of building heating energy in a cost-effective way, and ultimately contribute to the relief of global energy and climate issues.Energy wasted for heating the empty space of the entire building can be saved by passively heating the immediate environment around the human body. Here, the authors show a nanophotonic structure textile with tailored infrared property for passive personal heating using nanoporous metallized polyethylene.

  10. High-density nanopore array for selective biomolecule transport.

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Kamlesh D.

    2011-11-01

    Development of sophisticated tools capable of manipulating molecules at their own length scale enables new methods for chemical synthesis and detection. Although nanoscale devices have been developed to perform individual tasks, little work has been done on developing a truly scalable platform: a system that combines multiple components for sequential processing, as well as simultaneously processing and identifying the millions of potential species that may be present in a biological sample. The development of a scalable micro-nanofluidic device is limited in part by the ability to combine different materials (polymers, metals, semiconductors) onto a single chip, and the challenges with locally controlling the chemical, electrical, and mechanical properties within a micro or nanochannel. We have developed a unique construct known as a molecular gate: a multilayered polymer based device that combines microscale fluid channels with nanofluidic interconnects. Molecular gates have been demonstrated to selectively transport molecules between channels based on size or charge. In order to fully utilize these structures, we need to develop methods to actively control transport and identify species inside a nanopore. While previous work has been limited to creating electrical connections off-channel or metallizing the entire nanopore wall, we now have the ability to create multiple, separate conductive connections at the interior surface of a nanopore. These interior electrodes will be used for direct sensing of biological molecules, probing the electrical potential and charge distribution at the surface, and to actively turn on and off electrically driven transport of molecules through nanopores.

  11. Ergodicity of a single particle confined in a nanopore

    DEFF Research Database (Denmark)

    Bernardi, S.; Hansen, Jesper Schmidt; Frascolli, F.

    2012-01-01

    -ergodic component of the phase space for energy levels typical of experiments, is surprisingly small, i.e. we conclude that the ergodic hypothesis is a reasonable approximation even for a single particle trapped in a nanopore. Due to the numerical scope of this work, our focus will be the onset of ergodic behavior...

  12. Probe DNA-Cisplatin Interaction with Solid-State Nanopores

    Science.gov (United States)

    Zhou, Zhi; Hu, Ying; Li, Wei; Xu, Zhi; Wang, Pengye; Bai, Xuedong; Shan, Xinyan; Lu, Xinghua; Nanopore Collaboration

    2014-03-01

    Understanding the mechanism of DNA-cisplatin interaction is essential for clinical application and novel drug design. As an emerging single-molecule technology, solid-state nanopore has been employed in biomolecule detection and probing DNA-molecule interactions. Herein, we reported a real-time monitoring of DNA-cisplatin interaction by employing solid-state SiN nanopores. The DNA-cisplatin interacting process is clearly classified into three stages by measuring the capture rate of DNA-cisplatin adducts. In the first stage, the negative charged DNA molecules were partially discharged due to the bonding of positive charged cisplatin and forming of mono-adducts. In the second stage, forming of DNA-cisplatin di-adducts with the adjacent bases results in DNA bending and softening. The capture rate increases since the softened bi-adducts experience a lower barrier to thread into the nanopores. In the third stage, complex structures, such as micro-loop, are formed and the DNA-cisplatin adducts are aggregated. The capture rate decreases to zero as the aggregated adduct grows to the size of the pore. The characteristic time of this stage was found to be linear with the diameter of the nanopore and this dynamic process can be described with a second-order reaction model. We are grateful to Laboratory of Microfabrication, Dr. Y. Yao, and Prof. R.C. Yu (Institute of Physics, Chinese Academy of Sciences) for technical assistance.

  13. Concentration Polarization in Translocation of DNA through Nanopores and Nanochannels

    NARCIS (Netherlands)

    Das, S.; Dubsky, P.; van den Berg, Albert; Eijkel, Jan C.T.

    2012-01-01

    In this Letter we provide a theory to show that high-field electrokinetic translocation of DNA through nanopores or nanochannels causes large transient variations of the ionic concentrations in front and at the back of the DNA due to concentration polarization (CP). The CP causes strong local

  14. Nanopore fabricated in pyramidal HfO2 film by dielectric breakdown method

    Science.gov (United States)

    Wang, Yifan; Chen, Qi; Deng, Tao; Liu, Zewen

    2017-10-01

    The dielectric breakdown method provides an innovative solution to fabricate solid-state nanopores on insulating films. A nanopore generation event via this method is considered to be caused by random charged traps (i.e., structural defects) and high electric fields in the membrane. Thus, the position and number of nanopores on planar films prepared by the dielectric breakdown method is hard to control. In this paper, we propose to fabricate nanopores on pyramidal HfO2 films (10-nm and 15-nm-thick) to improve the ability to control the location and number during the fabrication process. Since the electric field intensity gets enhanced at the corners of the pyramid-shaped film, the probability of nanopore occurrence at vertex and edge areas increases. This priority of appearance provides us chance to control the location and number of nanopores by monitoring a sudden irreversible discrete increase in current. The experimental results showed that the probability of nanopore occurrence decreases in an order from the vertex area, the edge area to the side face area. The sizes of nanopores ranging from 30 nm to 10 nm were obtained. Nanopores fabricated on the pyramid-shaped HfO2 film also showed an obvious ion current rectification characteristic, which might improve the nanopore performance as a biomolecule sequencing platform.

  15. Multichannel detection of ionic currents through two nanopores fabricated on integrated Si3N4 membranes.

    Science.gov (United States)

    Yanagi, Itaru; Akahori, Rena; Aoki, Mayu; Harada, Kunio; Takeda, Ken-Ichi

    2016-08-16

    Integration of solid-state nanopores and multichannel detection of signals from each nanopore are effective measures for realizing high-throughput nanopore sensors. In the present study, we demonstrated fabrication of Si3N4 membrane arrays and the simultaneous measurement of ionic currents through two nanopores formed in two adjacent membranes. Membranes with thicknesses as low as 6.4 nm and small nanopores with diameters of less than 2 nm could be fabricated using the poly-Si sacrificial-layer process and multilevel pulse-voltage injection. Using the fabricated nanopore membranes, we successfully achieved simultaneous detection of clear ionic-current blockades when single-stranded short homopolymers (poly(dA)60) passed through two nanopores. In addition, we investigated the signal crosstalk and leakage current among separated chambers. When two nanopores were isolated on the front surface of the membrane, there was no signal crosstalk or leakage current between the chambers. However, when two nanopores were isolated on the backside of the Si substrate, signal crosstalk and leakage current were observed owing to high-capacitance coupling between the chambers and electrolysis of water on the surface of the Si substrate. The signal crosstalk and leakage current could be suppressed by oxidizing the exposed Si surface in the membrane chip. Finally, the observed ionic-current blockade when poly(dA)60 passed through the nanopore in the oxidized chip was approximately half of that observed in the non-oxidized chip.

  16. Phosphorene-directed self-assembly of asymmetric PS-b-PMMA block copolymer for perpendicularly-oriented sub-10 nm PS nanopore arrays

    Science.gov (United States)

    Zhang, Ziming; Zheng, Lu; Khurram, Muhammad; Yan, Qingfeng

    2017-10-01

    Few-layer black phosphorus, also known as phosphorene, is a new two-dimensional material which is of enormous interest for applications, mainly in electronics and optoelectronics. Herein, we for the first time employ phosphorene for directing the self-assembly of asymmetric polystyrene-block-polymethylmethacrylate (PS-b-PMMA) block copolymer (BCP) thin film to form the perpendicular orientation of sub-10 nm PS nanopore arrays in a hexagonal fashion normal to the interface. We experimentally demonstrate that none of the PS and PMMA blocks exhibit preferential affinity to the phosphorene-modified surface. Furthermore, the perpendicularly-oriented PS nanostructures almost stay unchanged with the variation of number of layers of few-layer phosphorene nanoflakes between 15-30 layers. Differing from the neutral polymer brushes which are widely used for chemical modification of the silicon substrate, phosphorene provides a novel physical way to control the interfacial interactions between the asymmetric PS-b-PMMA BCP thin film and the silicon substrate. Based on our results, it is possible to build a new scheme for producing sub-10 nm PS nanopore arrays oriented perpendicularly to the few-layer phosphorene nanoflakes. Furthermore, the nanostructural microdomains could serve as a promising nanolithography template for surface patterning of phosphorene nanoflakes.

  17. Phosphorene-directed self-assembly of asymmetric PS-b-PMMA block copolymer for perpendicularly-oriented sub-10 nm PS nanopore arrays.

    Science.gov (United States)

    Zhang, Ziming; Zheng, Lu; Khurram, Muhammad; Yan, Qingfeng

    2017-10-20

    Few-layer black phosphorus, also known as phosphorene, is a new two-dimensional material which is of enormous interest for applications, mainly in electronics and optoelectronics. Herein, we for the first time employ phosphorene for directing the self-assembly of asymmetric polystyrene-block-polymethylmethacrylate (PS-b-PMMA) block copolymer (BCP) thin film to form the perpendicular orientation of sub-10 nm PS nanopore arrays in a hexagonal fashion normal to the interface. We experimentally demonstrate that none of the PS and PMMA blocks exhibit preferential affinity to the phosphorene-modified surface. Furthermore, the perpendicularly-oriented PS nanostructures almost stay unchanged with the variation of number of layers of few-layer phosphorene nanoflakes between 15-30 layers. Differing from the neutral polymer brushes which are widely used for chemical modification of the silicon substrate, phosphorene provides a novel physical way to control the interfacial interactions between the asymmetric PS-b-PMMA BCP thin film and the silicon substrate. Based on our results, it is possible to build a new scheme for producing sub-10 nm PS nanopore arrays oriented perpendicularly to the few-layer phosphorene nanoflakes. Furthermore, the nanostructural microdomains could serve as a promising nanolithography template for surface patterning of phosphorene nanoflakes.

  18. Geochemistry of silicon isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Tiping; Li, Yanhe; Gao, Jianfei; Hu, Bin [Chinese Academy of Geological Science, Beijing (China). Inst. of Mineral Resources; Jiang, Shaoyong [China Univ. of Geosciences, Wuhan (China).

    2018-04-01

    Silicon is one of the most abundant elements in the Earth and silicon isotope geochemistry is important in identifying the silicon source for various geological bodies and in studying the behavior of silicon in different geological processes. This book starts with an introduction on the development of silicon isotope geochemistry. Various analytical methods are described and compared with each other in detail. The mechanisms of silicon isotope fractionation are discussed, and silicon isotope distributions in various extraterrestrial and terrestrial reservoirs are updated. Besides, the applications of silicon isotopes in several important fields are presented.

  19. Selective hierarchical patterning of silicon nanostructures via soft nanostencil lithography.

    Science.gov (United States)

    Du, Ke; Ding, Junjun; Wathuthanthri, Ishan; Choi, Chang-Hwan

    2017-11-17

    It is challenging to hierarchically pattern high-aspect-ratio nanostructures on microstructures using conventional lithographic techniques, where photoresist (PR) film is not able to uniformly cover on the microstructures as the aspect ratio increases. Such non-uniformity causes poor definition of nanopatterns over the microstructures. Nanostencil lithography can provide an alternative means to hierarchically construct nanostructures on microstructures via direct deposition or plasma etching through a free-standing nanoporous membrane. In this work, we demonstrate the multiscale hierarchical fabrication of high-aspect-ratio nanostructures on microstructures of silicon using a free-standing nanostencil, which is a nanoporous membrane consisting of metal (Cr), PR, and anti-reflective coating. The nanostencil membrane is used as a deposition mask to define Cr nanodot patterns on the predefined silicon microstructures. Then, deep reactive ion etching is used to hierarchically create nanostructures on the microstructures using the Cr nanodots as an etch mask. With simple modification of the main fabrication processes, high-aspect-ratio nanopillars are selectively defined only on top of the microstructures, on bottom, or on both top and bottom.

  20. Development of a 3D origami multiplex electrochemical immunodevice using a nanoporous silver-paper electrode and metal ion functionalized nanoporous gold-chitosan.

    Science.gov (United States)

    Li, Weiping; Li, Long; Li, Meng; Yu, Jinghua; Ge, Shenguang; Yan, Mei; Song, Xianrang

    2013-10-25

    A simple and sensitive 3D microfluidic origami multiplex electrochemical immunodevice was developed for the first time using a novel nanoporous silver modified paper working electrode as a sensor platform and different metal ion functionalized nanoporous gold-chitosan as a tracer.

  1. Nanoporous-carbon adsorbers for chemical microsensors.

    Energy Technology Data Exchange (ETDEWEB)

    Overmyer, Donald L.; Siegal, Michael P.; Staton, Alan W.; Provencio, Paula Polyak; Yelton, William Graham

    2004-11-01

    Chemical microsensors rely on partitioning of airborne chemicals into films to collect and measure trace quantities of hazardous vapors. Polymer sensor coatings used today are typically slow to respond and difficult to apply reproducibly. The objective of this project was to produce a durable sensor coating material based on graphitic nanoporous-carbon (NPC), a new material first studied at Sandia, for collection and detection of volatile organic compounds (VOC), toxic industrial chemicals (TIC), chemical warfare agents (CWA) and nuclear processing precursors (NPP). Preliminary studies using NPC films on exploratory surface-acoustic-wave (SAW) devices and as a {micro}ChemLab membrane preconcentrator suggested that NPC may outperform existing, irreproducible coatings for SAW sensor and {micro}ChemLab preconcentrator applications. Success of this project will provide a strategic advantage to the development of a robust, manufacturable, highly-sensitive chemical microsensor for public health, industrial, and national security needs. We use pulsed-laser deposition to grow NPC films at room-temperature with negligible residual stress, and hence, can be deposited onto nearly any substrate material to any thickness. Controlled deposition yields reproducible NPC density, morphology, and porosity, without any discernable variation in surface chemistry. NPC coatings > 20 {micro}m thick with density < 5% that of graphite have been demonstrated. NPC can be 'doped' with nearly any metal during growth to provide further enhancements in analyte detection and selectivity. Optimized NPC-coated SAW devices were compared directly to commonly-used polymer coated SAWs for sensitivity to a variety of VOC, TIC, CWA and NPP. In every analyte, NPC outperforms each polymer coating by multiple orders-of-magnitude in detection sensitivity, with improvements ranging from 103 to 108 times greater detection sensitivity! NPC-coated SAW sensors appear capable of detecting most analytes

  2. Electronic conductance model in constricted MoS{sub 2} with nanopores

    Energy Technology Data Exchange (ETDEWEB)

    Sarathy, Aditya [Beckman Institute for Advanced Science and Technology, University of Illinois, Urbana, Illinois 61801 (United States); Department of Electrical and Computer Engineering, University of Illinois, Urbana, Illinois 61801 (United States); Leburton, Jean-Pierre, E-mail: jleburto@illinois.edu [Beckman Institute for Advanced Science and Technology, University of Illinois, Urbana, Illinois 61801 (United States); Department of Electrical and Computer Engineering, University of Illinois, Urbana, Illinois 61801 (United States); Department of Physics, University of Illinois, Urbana, Illinois 61801 (United States)

    2016-02-01

    We describe a self-consistent model for electronic transport in a molybdenum di-sulphide (MoS{sub 2}) layer containing a nanopore in a constricted geometry. Our approach is based on a semi-classical thermionic Poisson-Boltzmann technique using a two-valley model within the effective mass approximation to investigate perturbations caused by the nanopore on the electronic current. In particular, we show that the effect of the nanopore on the conductance is reduced as the nanopore is moved from the center to the layer edges. Our model is applied to the detection of DNA translocating through the nanopore, which reveals current features similar to those as predicted in nanopore graphene layers.

  3. Theoretical and experimental studies on ionic currents in nanopore-based biosensors.

    Science.gov (United States)

    Liu, Lei; Li, Chu; Ma, Jian; Wu, Yingdong; Ni, Zhonghua; Chen, Yunfei

    2014-12-01

    Novel generation of analytical technology based on nanopores has provided possibilities to fabricate nanofluidic devices for low-cost DNA sequencing or rapid biosensing. In this paper, a simplified model was suggested to describe DNA molecule's translocation through a nanopore, and the internal potential, ion concentration, ionic flowing speed and ionic current in nanopores with different sizes were theoretically calculated and discussed on the basis of Poisson-Boltzmann equation, Navier-Stokes equation and Nernst-Planck equation by considering several important parameters, such as the applied voltage, the thickness and the electric potential distributions in nanopores. In this way, the basic ionic currents, the modulated ionic currents and the current drops induced by translocation were obtained, and the size effects of the nanopores were carefully compared and discussed based on the calculated results and experimental data, which indicated that nanopores with a size of 10 nm or so are more advantageous to achieve high quality ionic current signals in DNA sensing.

  4. Molecular sieving through a graphene nanopore: non-equilibrium molecular dynamics simulation

    Institute of Scientific and Technical Information of China (English)

    Chengzhen Sun; Bofeng Bai

    2017-01-01

    Two-dimensional graphene nanopores have shown great promise as ultra-permeable molecular sieves based on their size-sieving effects.We design a nitrogen/hydrogen modified graphene nanopore and conduct a transient non-equilibrium molecular dynamics simulation on its molecular sieving effects.The distinct time-varying molecular crossing numbers show that this special nanopore can efficiently sieve CO2 and H2S molecules from CH4 molecules with high selectivity.By analyzing the molecular structure and pore functionalization-related molecular orientation and permeable zone in the nanopore,density distribution in the molecular adsorption layer on the graphene surface,as well as other features,the molecular sieving mechanisms of graphene nanopores are revealed.Finally,several implications on the design of highly-efficient graphene nanopores,especially for determining the porosity and chemical functionalization,as gas separation membranes are summarized based on the identified phenomena and mechanisms.

  5. Alumina plate containing photosystem I reaction center complex oriented inside plate-penetrating silica nanopores.

    Science.gov (United States)

    Kamidaki, Chihiro; Kondo, Toru; Noji, Tomoyasu; Itoh, Tetsuji; Yamaguchi, Akira; Itoh, Shigeru

    2013-08-22

    The photosynthetic photosystem I reaction center complex (PSI-RC), which has a molecular diameter of 21 nm with 100 pigments, was incorporated into silica nanopores with a 100-nm diameter that penetrates an alumina plate of 60-μm thickness to make up an inorganic-biological hybrid photocell. PSI-RCs, purified from a thermophilic cyanobacterium, were stable inside the nanopores and rapidly photoreduced a mediator dye methyl viologen. The reduced dye was more stable inside nanopores suggesting the decrease of dissolved oxygen. The analysis by a cryogenic electron spin paramagnetic resonance indicated the oriented arrangement of RCs inside the 100-nm nanopores, with their surface parallel to the silica wall and perpendicular to the plane of the alumina plate. PSI RC complex in the semicrystalline orientation inside silica nanopores can be a new type of light energy conversion unit to supply strong reducing power selectively to other molecules inside or outside nanopores.

  6. Hierarchically structured nanoporous carbon tubes for high pressure carbon dioxide adsorption

    Directory of Open Access Journals (Sweden)

    Julia Patzsch

    2017-05-01

    Full Text Available Mesoscopic, nanoporous carbon tubes were synthesized by a combination of the Stoeber process and the use of electrospun macrosized polystyrene fibres as structure directing templates. The obtained carbon tubes have a macroporous nature characterized by a thick wall structure and a high specific surface area of approximately 500 m²/g resulting from their micro- and mesopores. The micropore regime of the carbon tubes is composed of turbostratic graphitic areas observed in the microstructure. The employed templating process was also used for the synthesis of silicon carbide tubes. The characterization of all porous materials was performed by nitrogen adsorption at 77 K, Raman spectroscopy, infrared spectroscopy, thermal gravimetric analysis (TGA, scanning electron microscopy (SEM as well as transmission electron microscopy (TEM. The adsorption of carbon dioxide on the carbon tubes at 25 °C at pressures of up to 30 bar was studied using a volumetric method. At 26 bar, an adsorption capacity of 4.9 mmol/g was observed. This is comparable to the adsorption capacity of molecular sieves and vertically aligned carbon nanotubes. The high pressure adsorption process of CO2 was found to irreversibly change the microporous structure of the carbon tubes.

  7. Influence of defects on the ordering degree of nanopores made from anodic aluminum oxide

    International Nuclear Information System (INIS)

    Yu Wenhui; Fei Guangtao; Chen Xiaomeng; Xue Fanghong; Xu Xijin

    2006-01-01

    Anodic aluminum oxide (AAO) templates with highly ordered nanoporous structure were fabricated by means of the electrochemical anodization under the constant anodic voltage and electrolyte temperature. The dependence of the ordering degree of nanopores on the point defects, dislocation configuration and grain boundary of aluminum is qualitatively analyzed. Experiment results show that the size of the ordered region of nanopores depends strongly on the point defects, dislocation cell configuration

  8. Stochastic nanopore sensors for the detection of terrorist agents: Current status and challenges

    Energy Technology Data Exchange (ETDEWEB)

    Liu Aihua; Zhao Qitao [Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington, TX 76019-0065 (United States); Guan Xiyun, E-mail: xguan@uta.edu [Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington, TX 76019-0065 (United States)

    2010-08-24

    Nanopore stochastic sensor works by monitoring the ionic current modulations induced by the passage of analytes of interest through a single pore, which can be obtained from a biological ion channel by self-assembly or artificially fabricated in a solid-state membrane. In this minireview, we overview the use of biological nanopores and artificial nanopores for the detection of terrorist agents including explosives, organophosphorus nerve agents, nitrogen mustards, organoarsenic compounds, toxins, and viruses. We also discuss the current challenge in the development of deployable nanopore sensors for real-world applications.

  9. Nanochannel Device with Embedded Nanopore: a New Approach for Single-Molecule DNA Analysis and Manipulation

    Science.gov (United States)

    Zhang, Yuning; Reisner, Walter

    2013-03-01

    Nanopore and nanochannel based devices are robust methods for biomolecular sensing and single DNA manipulation. Nanopore-based DNA sensing has attractive features that make it a leading candidate as a single-molecule DNA sequencing technology. Nanochannel based extension of DNA, combined with enzymatic or denaturation-based barcoding schemes, is already a powerful approach for genome analysis. We believe that there is revolutionary potential in devices that combine nanochannels with embedded pore detectors. In particular, due to the fast translocation of a DNA molecule through a standard nanopore configuration, there is an unfavorable trade-off between signal and sequence resolution. With a combined nanochannel-nanopore device, based on embedding a pore inside a nanochannel, we can in principle gain independent control over both DNA translocation speed and sensing signal, solving the key draw-back of the standard nanopore configuration. We demonstrate that we can optically detect successful translocation of DNA from the nanochannel out through the nanopore, a possible method to 'select' a given barcode for further analysis. In particular, we show that in equilibrium DNA will not escape through an embedded sub-persistence length nanopore, suggesting that the pore could be used as a nanoscale window through which to interrogate a nanochannel extended DNA molecule. Furthermore, electrical measurements through the nanopore are performed, indicating that DNA sensing is feasible using the nanochannel-nanopore device.

  10. Gradient and alternating diameter nanopore templates by focused ion beam guided anodization

    International Nuclear Information System (INIS)

    Chen Bo; Lu, Kathy; Tian Zhipeng

    2010-01-01

    Ordered arrays of anodic alumina nanopores with uniform pore diameters have been fabricated by self-organized anodization of aluminum. However, gradient or alternating diameter nanopore arrays with designed interpore distances have not been possible. In this study, focused ion beam lithography is used to fabricate hexagonally arranged concaves with different diameters in designed arrangements on aluminum surfaces. The patterns are then used to guide the further growth of alumina nanopores in the subsequent oxalic acid anodization. Gradient and alternating nanopore arrangements have been attained by FIB patterning guided oxalic acid anodization. The fundamental understanding of the process is discussed.

  11. Silicon based multilayer photoelectrodes for photoelectrolysis of water to produce hydrogen from the sun

    Science.gov (United States)

    Faruque, Faisal

    The main objective of this work is to study different materials for the direct photosynthesis of hydrogen from water. A variety of photocatalysts such as titanium dioxide, titanium oxy-nitride, silicon carbide, and gallium nitride are being investigated by others for the clean production of hydrogen for fuel cells and hydrogen economy. Our approach was to deposit suitable metallic regions on photocatalyst nanoparticles to direct the efficient synthesis of hydrogen to a particular site for convenient collection. We studied different electrode metals such as gold, platinum, titanium, palladium, and tungsten. We also studied different solar cell materials such as silicon (p- and n-types), silicon carbide and titanium dioxide semiconductors in order to efficiently generate electrons under illumination. We introduced a novel silicon-based multilayer photosynthesis device to take advantage of suitable properties of silicon and tungsten to efficiently produce hydrogen. The device consisted of a silicon (0.5mm) substrate, a deposited atomic layer of Al2O 3 (1nm), a doped polysilicon (0.1microm), and finally a tungsten nanoporous (5-10nm) layer acting as an interface electrode with water. The Al2O 3 layer was introduced to reduce leakage current and to prevent the spreading of the diffused p-n junction layer between the silicon and doped polysilicon layers. The surface of the photoelectrode was coated with nanotextured tungsten nanopores (TNP), which increased the surface area of the electrodes to the electrolyte, assisting in electron-hole mobility, and acting as a photocatalyst. The reported device exhibited a fill factor (%FF) of 27.22% and solar-to-hydrogen conversion efficiency of 0.03174%. This thesis describes the structures of the device, and offers a characterization and comparison between different photoelectrodes.

  12. Imbibition Triggered by Capillary Condensation in Nanopores.

    Science.gov (United States)

    Vincent, Olivier; Marguet, Bastien; Stroock, Abraham D

    2017-02-21

    We study the spatiotemporal dynamics of water uptake by capillary condensation from unsaturated vapor in mesoporous silicon layers (pore radius r p ≃ 2 nm), taking advantage of the local changes in optical reflectance as a function of water saturation. Our experiments elucidate two qualitatively different regimes as a function of the imposed external vapor pressure: at low vapor pressures, equilibration occurs via a diffusion-like process; at high vapor pressures, an imbibition-like wetting front results in fast equilibration toward a fully saturated sample. We show that the imbibition dynamics can be described by a modified Lucas-Washburn equation that takes into account the liquid stresses implied by Kelvin equation.

  13. Micropore and nanopore fabrication in hollow antiresonant reflecting optical waveguides.

    Science.gov (United States)

    Holmes, Matthew R; Shang, Tao; Hawkins, Aaron R; Rudenko, Mikhail; Measor, Philip; Schmidt, Holger

    2010-01-01

    We demonstrate the fabrication of micropore and nanopore features in hollow antiresonant reflecting optical waveguides to create an electrical and optical analysis platform that can size select and detect a single nanoparticle. Micropores (4 μm diameter) are reactive-ion etched through the top SiO(2) and SiN layers of the waveguides, leaving a thin SiN membrane above the hollow core. Nanopores are formed in the SiN membranes using a focused ion-beam etch process that provides control over the pore size. Openings as small as 20 nm in diameter are created. Optical loss measurements indicate that micropores did not significantly alter the loss along the waveguide.

  14. Non-dissipative energy capture of confined liquid in nanopores

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Baoxing; Chen, Xi [Columbia Nanomechanics Research Center, Department of Earth and Environmental Engineering, Columbia University, New York, New York 10027 (United States); Lu, Weiyi; Zhao, Cang [Department of Structural Engineering, University of California–San Diego, La Jolla, California 92093-0085 (United States); Qiao, Yu, E-mail: yqiao@ucsd.edu [Department of Structural Engineering, University of California–San Diego, La Jolla, California 92093-0085 (United States); Program of Materials Science and Engineering, University of California–San Diego, La Jolla, CA 92093 (United States)

    2014-05-19

    In the past, energy absorption of protection/damping materials is mainly based on energy dissipation, which causes a fundamental conflict between the requirements of safety/comfort and efficiency. In the current study, a nanofluidic “energy capture” system is reported, which is based on nanoporous materials and nonwetting liquid. Both molecular dynamics simulations and experiments show that as the liquid overcomes the capillary effect and infiltrates into the nanopores, the mechanical energy of a stress wave could be temporarily stored by the confined liquid phase and isolated from the wave energy transmission path. Such a system can work under a relatively low pressure for mitigating high-pressure stress waves, not necessarily involved in any energy dissipation processes.

  15. Non-dissipative energy capture of confined liquid in nanopores

    International Nuclear Information System (INIS)

    Xu, Baoxing; Chen, Xi; Lu, Weiyi; Zhao, Cang; Qiao, Yu

    2014-01-01

    In the past, energy absorption of protection/damping materials is mainly based on energy dissipation, which causes a fundamental conflict between the requirements of safety/comfort and efficiency. In the current study, a nanofluidic “energy capture” system is reported, which is based on nanoporous materials and nonwetting liquid. Both molecular dynamics simulations and experiments show that as the liquid overcomes the capillary effect and infiltrates into the nanopores, the mechanical energy of a stress wave could be temporarily stored by the confined liquid phase and isolated from the wave energy transmission path. Such a system can work under a relatively low pressure for mitigating high-pressure stress waves, not necessarily involved in any energy dissipation processes.

  16. InP nanopore arrays for photoelectrochemical hydrogen generation.

    Science.gov (United States)

    Li, Qiang; Zheng, Maojun; Zhang, Bin; Zhu, Changqing; Wang, Faze; Song, Jingnan; Zhong, Miao; Ma, Li; Shen, Wenzhong

    2016-02-19

    We report a facile and large-scale fabrication of highly ordered one-dimensional (1D) indium phosphide (InP) nanopore arrays (NPs) and their application as photoelectrodes for photoelectrochemical (PEC) hydrogen production. These InP NPs exhibit superior PEC performance due to their excellent light-trapping characteristics, high-quality 1D conducting channels and large surface areas. The photocurrent density of optimized InP NPs is 8.9 times higher than that of planar counterpart at an applied potential of +0.3 V versus RHE under AM 1.5G illumination (100 mW cm(-2)). In addition, the onset potential of InP NPs exhibits 105 mV of cathodic shift relative to planar control. The superior performance of the nanoporous samples is further explained by Mott-Schottky and electrochemical impedance spectroscopy ananlysis.

  17. Supercapacitive transport of pharmacologic agents using nanoporous gold electrodes.

    Science.gov (United States)

    Gittard, Shaun D; Pierson, Bonnie E; Ha, Cindy M; Wu, Chung-An Max; Narayan, Roger J; Robinson, David B

    2010-02-01

    In this study, nanoporous gold supercapacitors were produced by electrochemical dealloying of gold-silver alloy. Scanning electron microscopy and energy dispersive X-ray spectroscopy confirmed completion of the dealloying process and generation of a porous gold material with approximately 10 nm diameter pores. Cyclic voltammetry and chronoamperometry of the nanoporous gold electrodes indicated that these materials exhibited supercapacitor behavior. The storage capacity of the electrodes measured by chronoamperometry was approximately 3 mC at 200 mV. Electrochemical storage and voltage-controlled delivery of two model pharmacologic agents, benzylammonium and salicylic acid, was demonstrated. These results suggest that capacitance-based storage and delivery of pharmacologic agents may serve as an alternative to conventional drug delivery methods.

  18. Capacitance-Power-Hysteresis Trilemma in Nanoporous Supercapacitors

    Directory of Open Access Journals (Sweden)

    Alpha A. Lee

    2016-06-01

    Full Text Available Nanoporous supercapacitors are an important player in the field of energy storage that fill the gap between dielectric capacitors and batteries. The key challenge in the development of supercapacitors is the perceived trade-off between capacitance and power delivery. Current efforts to boost the capacitance of nanoporous supercapacitors focus on reducing the pore size so that they can only accommodate a single layer of ions. However, this tight packing compromises the charging dynamics and hence power density. We show via an analytical theory and Monte Carlo simulations that charging is sensitively dependent on the affinity of ions to the pores, and that high capacitances can be obtained for ionophobic pores of widths significantly larger than the ion diameter. Our theory also predicts that charging can be hysteretic with a significant energy loss per cycle for intermediate ionophilicities. We use these observations to explore the parameter regimes in which a capacitance-power-hysteresis trilemma may be avoided.

  19. Resizing metal-coated nanopores using a scanning electron microscope.

    Science.gov (United States)

    Chansin, Guillaume A T; Hong, Jongin; Dusting, Jonathan; deMello, Andrew J; Albrecht, Tim; Edel, Joshua B

    2011-10-04

    Electron beam-induced shrinkage provides a convenient way of resizing solid-state nanopores in Si(3) N(4) membranes. Here, a scanning electron microscope (SEM) has been used to resize a range of different focussed ion beam-milled nanopores in Al-coated Si(3) N(4) membranes. Energy-dispersive X-ray spectra and SEM images acquired during resizing highlight that a time-variant carbon deposition process is the dominant mechanism of pore shrinkage, although granular structures on the membrane surface in the vicinity of the pores suggest that competing processes may occur. Shrinkage is observed on the Al side of the pore as well as on the Si(3) N(4) side, while the shrinkage rate is observed to be dependent on a variety of factors. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Titanium nitride stamps replicating nanoporous anodic alumina films

    International Nuclear Information System (INIS)

    Navas, D; Sanchez, O; Asenjo, A; Jaafar, M; Baldonedo, J L; Vazquez, M; Hernandez-Velez, M

    2007-01-01

    Fabrication of nanostructured TiN films by magnetron sputtering using nanoporous anodic alumina films (NAAF) as substrates is reported. These hard nanostructured films could be used for pre-patterning aluminium foils and to obtain nanoporous films replicating the starting NAAF over a wide range of pore diameters and spacings. Pre-patterned Al foils are obtained by compression with pressures lower than those previously reported, then a new NAAF can be fabricated by means of only one anodization process. As an example, one of the TiN stamps was used for pre-patterning an Al foil at a pressure of 200 kg cm -2 and then it was anodized in oxalic acid solution obtaining the corresponding replica of the starting NAAF

  1. Elastic constants of nanoporous III-V semiconductors

    Czech Academy of Sciences Publication Activity Database

    Janovská, Michaela; Sedlák, Petr; Kruisová, Alena; Seiner, Hanuš; Landa, Michal; Grym, Jan

    2015-01-01

    Roč. 48, č. 24 (2015) ISSN 0022-3727 R&D Projects: GA ČR GB14-36566G Institutional support: RVO:61388998 ; RVO:67985882 Keywords : nanoporous semiconductors * resonant ultrasound spectroscopy * finite elements modelling Subject RIV: BM - Solid Matter Physics ; Magnetism; BM - Solid Matter Physics ; Magnetism (URE-Y) Impact factor: 2.772, year: 2015 http://iopscience.iop.org/0022-3727/48/24/245102/article

  2. Mathematical modeling and simulation of nanopore blocking by precipitation

    KAUST Repository

    Wolfram, M-T

    2010-10-29

    High surface charges of polymer pore walls and applied electric fields can lead to the formation and subsequent dissolution of precipitates in nanopores. These precipitates block the pore, leading to current fluctuations. We present an extended Poisson-Nernst-Planck system which includes chemical reactions of precipitation and dissolution. We discuss the mathematical modeling and present 2D numerical simulations. © 2010 IOP Publishing Ltd.

  3. Parametric study of thin film evaporation from nanoporous membranes

    Science.gov (United States)

    Wilke, Kyle L.; Barabadi, Banafsheh; Lu, Zhengmao; Zhang, TieJun; Wang, Evelyn N.

    2017-10-01

    The performance and lifetime of advanced electronics are often dictated by the ability to dissipate heat generated within the device. Thin film evaporation from nanoporous membranes is a promising thermal management approach, which reduces the thermal transport distance across the liquid film while also providing passive capillary pumping of liquid to the evaporating interface. In this work, we investigated the dependence of thin film evaporation from nanoporous membranes on a variety of geometric parameters. Anodic aluminum oxide membranes were used as experimental templates, where pore radii of 28-75 nm, porosities of 0.1-0.35, and meniscus locations down to 1 μm within the pore were tested. We demonstrated different heat transfer regimes and observed more than an order of magnitude increase in dissipated heat flux by operating in the pore-level evaporation regime. The pore diameter had little effect on pore-level evaporation performance due to the negligible conduction resistance from the pore wall to the evaporating interface. The dissipated heat flux scaled with porosity as the evaporative area increased. Furthermore, moving the meniscus as little as 1 μm into the pore decreased the dissipated heat flux by more than a factor of two due to the added resistance to vapor escaping the pore. The experimental results elucidate thin film evaporation from nanopores and confirm findings of recent modeling efforts. This work also provides guidance for the design of future thin film evaporation devices for advanced thermal management. Furthermore, evaporation from nanopores is relevant to water purification, chemical separations, microfluidics, and natural processes such as transpiration.

  4. DeepSimulator: a deep simulator for Nanopore sequencing

    KAUST Repository

    Li, Yu

    2017-12-23

    Motivation: Oxford Nanopore sequencing is a rapidly developed sequencing technology in recent years. To keep pace with the explosion of the downstream data analytical tools, a versatile Nanopore sequencing simulator is needed to complement the experimental data as well as to benchmark those newly developed tools. However, all the currently available simulators are based on simple statistics of the produced reads, which have difficulty in capturing the complex nature of the Nanopore sequencing procedure, the main task of which is the generation of raw electrical current signals. Results: Here we propose a deep learning based simulator, DeepSimulator, to mimic the entire pipeline of Nanopore sequencing. Starting from a given reference genome or assembled contigs, we simulate the electrical current signals by a context-dependent deep learning model, followed by a base-calling procedure to yield simulated reads. This workflow mimics the sequencing procedure more naturally. The thorough experiments performed across four species show that the signals generated by our context-dependent model are more similar to the experimentally obtained signals than the ones generated by the official context-independent pore model. In terms of the simulated reads, we provide a parameter interface to users so that they can obtain the reads with different accuracies ranging from 83% to 97%. The reads generated by the default parameter have almost the same properties as the real data. Two case studies demonstrate the application of DeepSimulator to benefit the development of tools in de novo assembly and in low coverage SNP detection. Availability: The software can be accessed freely at: https://github.com/lykaust15/DeepSimulator.

  5. Drug loading of nanoporous TiO2 films

    International Nuclear Information System (INIS)

    Ayon, Arturo A; Cantu, Michael; Chava, Kalpana; Agrawal, C Mauli; Feldman, Marc D; Johnson, Dave; Patel, Devang; Marton, Denes; Shi, Emily

    2006-01-01

    The loading of therapeutic amounts of drug on a nanoporous TiO 2 surface is described. This novel drug-loading scheme on a biocompatible surface, when employed on medical implants, will benefit patients who require the deployment of drug-eluting implants. Anticoagulants, analgesics and antibiotics can be considered on the associated implants for drug delivery during the time of maximal pain or risk for patients undergoing orthopedic procedures. Therefore, this scheme will maximize the chances of patient recovery. (communication)

  6. Antibacterial Activity of Zinc Oxide-Coated Nanoporous Alumina

    Science.gov (United States)

    2012-05-17

    made nanoporous alumina membranes, which were created by means of anodic oxidation of aluminum in an oxalic acid electrolyte, for treatment of skin...this study. All of the solutions were prepared using 18 M de-ionized water (lab supply) and trace metal grade nitric acid (Thermo Fisher Scientific...low production cost, repro- ducible reproduction, and facile reproduction approach for these materials. Using in vitro studies, keratinocytes (HaCaT

  7. Effects of Confinement on Chemical Reaction Equilibrium in Nanoporous Materials

    Czech Academy of Sciences Publication Activity Database

    Smith, W.R.; Lísal, Martin; Brennan, J.K.

    2006-01-01

    Roč. 3984, - (2006), s. 743-751 ISSN 0302-9743 R&D Projects: GA ČR(CZ) GA203/05/0725; GA AV ČR 1ET400720507 Grant - others:NRCC(CA) OGP 1041 Institutional research plan: CEZ:AV0Z40720504 Keywords : nanoporous materials * chemical reaction equilibrium Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 0.402, year: 2005

  8. Nanoporous Polymer-Ceramic Composite Electrolytes for Lithium Metal Batteries

    KAUST Repository

    Tu, Zhengyuan

    2013-09-16

    A nanoporous composite material that offers the unique combination of high room-temperature ionic conductivity and high mechanical modulus is reported. When used as the separator/electrolyte in lithium batteries employing metallic lithium as anode, the material displays unprecedented cycling stability and excellent ability to prevent premature cell failure by dendrite-induced short circuits © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Warming up human body by nanoporous metallized polyethylene textile

    OpenAIRE

    Cai, Lili; Song, Alex Y.; Wu, Peilin; Hsu, Po-Chun; Peng, Yucan; Chen, Jun; Liu, Chong; Catrysse, Peter B.; Liu, Yayuan; Yang, Ankun; Zhou, Chenxing; Zhou, Chenyu; Fan, Shanhui; Cui, Yi

    2017-01-01

    Space heating accounts for the largest energy end-use of buildings that imposes significant burden on the society. The energy wasted for heating the empty space of the entire building can be saved by passively heating the immediate environment around the human body. Here, we demonstrate a nanophotonic structure textile with tailored infrared (IR) property for passive personal heating using nanoporous metallized polyethylene. By constructing an IR-reflective layer on an IR-transparent layer wi...

  10. Buried oxide layer in silicon

    Science.gov (United States)

    Sadana, Devendra Kumar; Holland, Orin Wayne

    2001-01-01

    A process for forming Silicon-On-Insulator is described incorporating the steps of ion implantation of oxygen into a silicon substrate at elevated temperature, ion implanting oxygen at a temperature below 200.degree. C. at a lower dose to form an amorphous silicon layer, and annealing steps to form a mixture of defective single crystal silicon and polycrystalline silicon or polycrystalline silicon alone and then silicon oxide from the amorphous silicon layer to form a continuous silicon oxide layer below the surface of the silicon substrate to provide an isolated superficial layer of silicon. The invention overcomes the problem of buried isolated islands of silicon oxide forming a discontinuous buried oxide layer.

  11. Mechanisms of water infiltration into conical hydrophobic nanopores.

    Science.gov (United States)

    Liu, Ling; Zhao, Jianbing; Yin, Chun-Yang; Culligan, Patricia J; Chen, Xi

    2009-08-14

    Fluid channels with inclined solid walls (e.g. cone- and slit-shaped pores) have wide and promising applications in micro- and nano-engineering and science. In this paper, we use molecular dynamics (MD) simulations to investigate the mechanisms of water infiltration (adsorption) into cone-shaped nanopores made of a hydrophobic graphene sheet. When the apex angle is relatively small, an external pressure is required to initiate infiltration and the pressure should keep increasing in order to further advance the water front inside the nanopore. By enlarging the apex angle, the pressure required for sustaining infiltration can be effectively lowered. When the apex angle is sufficiently large, under ambient condition water can spontaneously infiltrate to a certain depth of the nanopore, after which an external pressure is still required to infiltrate more water molecules. The unusual involvement of both spontaneous and pressure-assisted infiltration mechanisms in the case of blunt nanocones, as well as other unique nanofluid characteristics, is explained by the Young's relation enriched with the size effects of surface tension and contact angle in the nanoscale confinement.

  12. Surface effects on the mechanical properties of nanoporous materials

    International Nuclear Information System (INIS)

    Lu Zixing; Zhang Cungang; Liu Qiang; Yang Zhenyu

    2011-01-01

    In this paper, surface effects on the mechanical behaviour of nanoporous materials are investigated using the theory of surface elasticity and Timoshenko beam theory based on the tetrakaidecahedron (or Kelvin) open-cell foam model. Meanwhile, the influence of surface elasticity and residual surface stress on the mechanical properties of nanoporous materials is discussed. In addition, the results derived from the theory of Euler-Bernoulli beam model are also provided for comparison. Theoretical results show that the effective Young's modulus of the nanoporous materials increases as the diameter of the strut decreases, but in contrast Poisson's ratio and the brittle collapse strength decrease with the diameter of the strut. The contribution of shear deformation to surface effects on elastic properties is more significant, while the surface effects on brittle collapse strength are not sensitive to shear deformation, and it can even be neglected. As the strut size increases, the present results can be reduced to the cases without considering surface effects, which verifies the efficiency of the present model to a certain extent.

  13. Oxford Nanopore MinION Sequencing and Genome Assembly

    Directory of Open Access Journals (Sweden)

    Hengyun Lu

    2016-10-01

    Full Text Available The revolution of genome sequencing is continuing after the successful second-generation sequencing (SGS technology. The third-generation sequencing (TGS technology, led by Pacific Biosciences (PacBio, is progressing rapidly, moving from a technology once only capable of providing data for small genome analysis, or for performing targeted screening, to one that promises high quality de novo assembly and structural variation detection for human-sized genomes. In 2014, the MinION, the first commercial sequencer using nanopore technology, was released by Oxford Nanopore Technologies (ONT. MinION identifies DNA bases by measuring the changes in electrical conductivity generated as DNA strands pass through a biological pore. Its portability, affordability, and speed in data production makes it suitable for real-time applications, the release of the long read sequencer MinION has thus generated much excitement and interest in the genomics community. While de novo genome assemblies can be cheaply produced from SGS data, assembly continuity is often relatively poor, due to the limited ability of short reads to handle long repeats. Assembly quality can be greatly improved by using TGS long reads, since repetitive regions can be easily expanded into using longer sequencing lengths, despite having higher error rates at the base level. The potential of nanopore sequencing has been demonstrated by various studies in genome surveillance at locations where rapid and reliable sequencing is needed, but where resources are limited.

  14. Nanoporous ionic organic networks: from synthesis to materials applications.

    Science.gov (United States)

    Sun, Jian-Ke; Antonietti, Markus; Yuan, Jiayin

    2016-11-21

    The past decade has witnessed rapid progress in the synthesis of nanoporous organic networks or polymer frameworks for various potential applications. Generally speaking, functionalization of porous networks to add extra properties and enhance materials performance could be achieved either during the pore formation (thus a concurrent approach) or by post-synthetic modification (a sequential approach). Nanoporous organic networks which include ion pairs bound in a covalent manner are of special importance and possess extreme application profiles. Within these nanoporous ionic organic networks (NIONs), here with a pore size in the range from sub-1 nm to 100 nm, we observe a synergistic coupling of the electrostatic interaction of charges, the nanoconfinement within pores and the addressable functional units in soft matter resulting in a wide variety of functions and applications, above all catalysis, energy storage and conversion, as well as environment-related operations. This review aims to highlight the recent progress in this area, and seeks to raise original perspectives that will stimulate future advancements at both the fundamental and applied level.

  15. Nanoindentation and micro-compression testing of nanoporous gold

    Energy Technology Data Exchange (ETDEWEB)

    Epler, Eike; Volkert, Cynthia A. [Institut fuer Materialphysik, Georg-August-Universitaet Goettingen (Germany); Balk, T. John [Department of Chemical and Materials Engineering, University of Kentucky (United States)

    2009-07-01

    Recent studies on materials such as nanoporous Au have shown that the strength of open-cell foams can be increased at a fixed porosity by decreasing the foam length scale (ligament diameter and length). This effect is attributed to the difficulty of activating dislocations in sub-micron crystal volumes. If high strength nanoporous materials are to be used to advantage in technical applications, the details of the parameters determining their strength need to be understood. In this study, the mechanical response of nanoporous Au fabricated by electrochemical dissolution from a Au-Ag alloy, is investigated by indentation using a cube corner tip as well as by micro-compression testing of columns fabricated by focused ion beam machining. The tests reveal a significant time-dependence or creep behavior in the 30% relative density foam that is not observed in fully dense gold. The origins of this effect will be probed by varying the length scale of the foam. In addition, a large scatter in mechanical behavior, particularly in the elastic response, is observed from position to position and sample to sample, which is attributed to small variations in the open cell structure.

  16. Evolution of Surface Nanopores in Pressurised Gyrospun Polymeric Microfibers

    Directory of Open Access Journals (Sweden)

    U. Eranka Illangakoon

    2017-10-01

    Full Text Available The selection of a solvent or solvent system and the ensuing polymer–solvent interactions are crucial factors affecting the preparation of fibers with multiple morphologies. A range of poly(methylmethacrylate fibers were prepared by pressurised gyration using acetone, chloroform, N,N-dimethylformamide (DMF, ethyl acetate and dichloromethane as solvents. It was found that microscale fibers with surface nanopores were formed when using chloroform, ethyl acetate and dichloromethane and poreless fibers were formed when using acetone and DMF as the solvent. These observations are explained on the basis of the physical properties of the solvents and mechanisms of pore formation. The formation of porous fibers is caused by many solvent properties such as volatility, solubility parameters, vapour pressure and surface tension. Cross-sectional images show that the nanopores are only on the surface of the fibers and they were not inter-connected. Further, the results show that fibers with desired nanopores (40–400 nm can be prepared by carefully selecting the solvent and applied pressure in the gyration process.

  17. Monitoring tetracycline through a solid-state nanopore sensor

    Science.gov (United States)

    Zhang, Yuechuan; Chen, Yanling; Fu, Yongqi; Ying, Cuifeng; Feng, Yanxiao; Huang, Qimeng; Wang, Chao; Pei, De-Sheng; Wang, Deqiang

    2016-06-01

    Antibiotics as emerging environmental contaminants, are widely used in both human and veterinary medicines. A solid-state nanopore sensing method is reported in this article to detect Tetracycline, which is based on Tet-off and Tet-on systems. rtTA (reverse tetracycline-controlled trans-activator) and TRE (Tetracycline Responsive Element) could bind each other under the action of Tetracycline to form one complex. When the complex passes through nanopores with 8 ~ 9 nanometers in diameter, we could detect the concentrations of Tet from 2 ng/mL to 2000 ng/mL. According to the Logistic model, we could define three growth zones of Tetracycline for rtTA and TRE. The slow growth zone is 0-39.5 ng/mL. The rapid growth zone is 39.5-529.7 ng/mL. The saturated zone is > 529.7 ng/mL. Compared to the previous methods, the nanopore sensor could detect and quantify these different kinds of molecule at the single-molecule level.

  18. Selective Electrochemical Detection of Epinephrine Using Gold Nanoporous Film

    Directory of Open Access Journals (Sweden)

    Dina M. Fouad

    2016-01-01

    Full Text Available Epinephrine (EP is one of the important catecholamine neurotransmitters that play an important role in the mammalian central nervous system. Therefore, it is necessary to determine the change of its concentrations. Nanoporous materials have wide applications that include catalysis, energy storages, environmental pollution control, wastewater treatment, and sensing applications. These unique properties could be attributable to their high surface area, a large pore volume, and uniform pore sizes. A gold nanoporous layer modified gold electrode was prepared and applied for the selective determination of epinephrine neurotransmitter at low concentration in the presence of several other substances including ascorbic acid (AA and uric acid (UA. The constructed electrode was characterized using scanning electron microscopy and cyclic voltammetry. The resulting electrode showed a selective detection of epinephrine with the interferences of dopamine and uric acid over a wide linear range (from 50 μM to 1 mM. The coverage of gold nanoporous on the surface of gold electrode represents a promising electrochemical sensor with high selectivity and sensitivity.

  19. Understanding improved osteoblast behavior on select nanoporous anodic alumina

    Science.gov (United States)

    Ni, Siyu; Li, Changyan; Ni, Shirong; Chen, Ting; Webster, Thomas J

    2014-01-01

    The aim of this study was to prepare different sized porous anodic alumina (PAA) and examine preosteoblast (MC3T3-E1) attachment and proliferation on such nanoporous surfaces. In this study, PAA with tunable pore sizes (25 nm, 50 nm, and 75 nm) were fabricated by a two-step anodizing procedure in oxalic acid. The surface morphology and elemental composition of PAA were characterized by field emission scanning electron microscopy and X-ray photoelectron spectroscopy analysis. The nanopore arrays on all of the PAA samples were highly regular. X-ray photoelectron spectroscopy analysis suggested that the chemistry of PAA and flat aluminum surfaces were similar. However, contact angles were significantly greater on all of the PAA compared to flat aluminum substrates, which consequently altered protein adsorption profiles. The attachment and proliferation of preosteoblasts were determined for up to 7 days in culture using field emission scanning electron microscopy and a Cell Counting Kit-8. Results showed that nanoporous surfaces did not enhance initial preosteoblast attachment, whereas preosteoblast proliferation dramatically increased when the PAA pore size was either 50 nm or 75 nm compared to all other samples (Paluminum by modifying surface nano-roughness alone (and not changing chemistry) through an anodization process to improve osteoblast density, and, thus, should be further studied as a bioactive interface for orthopedic applications. PMID:25045263

  20. A Nanoporous Carbon/Exfoliated Graphite Composite For Supercapacitor Electrodes

    Science.gov (United States)

    Rosi, Memoria; Ekaputra, Muhamad P.; Iskandar, Ferry; Abdullah, Mikrajuddin; Khairurrijal

    2010-12-01

    Nanoporous carbon was prepared from coconut shells using a simple heating method. The nanoporous carbon is subjected to different treatments: without activation, activation with polyethylene glycol (PEG), and activation with sodium hydroxide (NaOH)-PEG. The exfoliated graphite was synthesized from graphite powder oxidized with zinc acetate (ZnAc) and intercalated with polyvinyl alcohol (PVA) and NaOH. A composite was made by mixing the nanoporous carbon with NaOH-PEG activation, the exfoliated graphite and a binder of PVA solution, grinding the mixture, and annealing it using ultrasonic bath for 1 hour. All of as-synthesized materials were characterized by employing a scanning electron microscope (SEM), a MATLAB's image processing toolbox, and an x-ray diffractometer (XRD). It was confirmed that the composite is crystalline with (002) and (004) orientations. In addition, it was also found that the composite has a high surface area, a high distribution of pore sizes less than 40 nm, and a high porosity (67%). Noting that the pore sizes less than 20 nm are significant for ionic species storage and those in the range of 20 to 40 nm are very accessible for ionic clusters mobility across the pores, the composite is a promising material for the application as supercapacitor electrodes.

  1. Modeling of 1D Anomalous Diffusion in Fractured Nanoporous Media

    Directory of Open Access Journals (Sweden)

    Albinali Ali

    2016-07-01

    Full Text Available Fractured nanoporous reservoirs include multi-scale and discontinuous fractures coupled with a complex nanoporous matrix. Such systems cannot be described by the conventional dual-porosity (or multi-porosity idealizations due to the presence of different flow mechanisms at multiple scales. More detailed modeling approaches, such as Discrete Fracture Network (DFN models, similarly suffer from the extensive data requirements dictated by the intricacy of the flow scales, which eventually deter the utility of these models. This paper discusses the utility and construction of 1D analytical and numerical anomalous diffusion models for heterogeneous, nanoporous media, which is commonly encountered in oil and gas production from tight, unconventional reservoirs with fractured horizontal wells. A fractional form of Darcy’s law, which incorporates the non-local and hereditary nature of flow, is coupled with the classical mass conservation equation to derive a fractional diffusion equation in space and time. Results show excellent agreement with established solutions under asymptotic conditions and are consistent with the physical intuitions.

  2. An engineered ClyA nanopore detects folded target proteins by selective external association and pore entry.

    NARCIS (Netherlands)

    Soskine, Mikhael; Biesemans, Annemie; Moeyaert, Benjamien; Cheley, Stephen; Bayley, Hagan; Maglia, Giovanni

    Nanopores have been used in label-free single-molecule studies, including investigations of chemical reactions, nucleic acid analysis, and applications in sensing. Biological nanopores generally perform better than artificial nanopores as sensors, but they have disadvantages including a fixed

  3. Using Synthetic Nanopores for Single-Molecule Analyses: Detecting SNPs, Trapping DNA Molecules, and the Prospects for Sequencing DNA

    Science.gov (United States)

    Dimitrov, Valentin V.

    2009-01-01

    This work focuses on studying properties of DNA molecules and DNA-protein interactions using synthetic nanopores, and it examines the prospects of sequencing DNA using synthetic nanopores. We have developed a method for discriminating between alleles that uses a synthetic nanopore to measure the binding of a restriction enzyme to DNA. There exists…

  4. Laser shock ignition of porous silicon based nano-energetic films

    International Nuclear Information System (INIS)

    Plummer, A.; Gascooke, J.; Shapter, J.; Kuznetsov, V. A.; Voelcker, N. H.

    2014-01-01

    Nanoporous silicon films on a silicon wafer were loaded with sodium perchlorate and initiated using illumination with infrared laser pulses to cause laser thermal ignition and laser-generated shock waves. Using Photon Doppler Velocimetry, it was determined that these waves are weak stress waves with a threshold intensity of 131 MPa in the silicon substrate. Shock generation was achieved through confinement of a plasma, generated upon irradiation of an absorptive paint layer held against the substrate side of the wafer. These stress waves were below the threshold required for sample fracturing. Exploiting either the laser thermal or laser-generated shock mechanisms of ignition may permit use of pSi energetic materials in applications otherwise precluded due to their environmental sensitivity

  5. Laser shock ignition of porous silicon based nano-energetic films

    Energy Technology Data Exchange (ETDEWEB)

    Plummer, A.; Gascooke, J.; Shapter, J. [School of Chemical and Physical Sciences, Flinders University, 5042, Bedford Park (Australia); Centre of Expertise in Energetic Materials (CEEM), Bedford Park (Australia); Kuznetsov, V. A., E-mail: nico.voelcker@unisa.edu.au, E-mail: Valerian.Kuznetsov@dsto.defence.gov.au [School of Chemical and Physical Sciences, Flinders University, 5042, Bedford Park (Australia); Centre of Expertise in Energetic Materials (CEEM), Bedford Park (Australia); Weapons and Combat Systems Division, Defence Science and Technology Organisation, Edinburgh 5111 (Australia); Voelcker, N. H., E-mail: nico.voelcker@unisa.edu.au, E-mail: Valerian.Kuznetsov@dsto.defence.gov.au [Mawson Institute, University of South Australia, 5095, Mawson Lakes (Australia)

    2014-08-07

    Nanoporous silicon films on a silicon wafer were loaded with sodium perchlorate and initiated using illumination with infrared laser pulses to cause laser thermal ignition and laser-generated shock waves. Using Photon Doppler Velocimetry, it was determined that these waves are weak stress waves with a threshold intensity of 131 MPa in the silicon substrate. Shock generation was achieved through confinement of a plasma, generated upon irradiation of an absorptive paint layer held against the substrate side of the wafer. These stress waves were below the threshold required for sample fracturing. Exploiting either the laser thermal or laser-generated shock mechanisms of ignition may permit use of pSi energetic materials in applications otherwise precluded due to their environmental sensitivity.

  6. Nanoporous materials for reducing the over potential of creating hydrogen by water electrolysis

    Science.gov (United States)

    Anderson, Marc A.; Leonard, Kevin C.

    2016-06-14

    Disclosed is an electrolyzer including an electrode including a nanoporous oxide-coated conducting material. Also disclosed is a method of producing a gas through electrolysis by contacting an aqueous solution with an electrode connected to an electrical power source, wherein the electrode includes a nanoporous oxide-coated conducting material.

  7. Sodium Dodecyl Sulfate (SDS)-Loaded Nanoporous Polymer as Anti-Biofilm Surface Coating Material

    DEFF Research Database (Denmark)

    Li, Li; Molin, Søren; Yang, Liang

    2013-01-01

    -b-polydimethylsiloxane (1,2-PB-b-PDMS) block copolymer via chemical cross-linking of the 1,2-PB block followed by quantitative removal of the PDMS block. Sodium dodecyl sulfate (SDS) was loaded into the nanoporous 1,2-PB from aqueous solution. The SDS-loaded nanoporous polymer films were shown to block bacterial attachment...

  8. Electrokinetic transport of nanoparticles to opening of nanopores on cell membrane during electroporation

    Energy Technology Data Exchange (ETDEWEB)

    Movahed, Saeid [University of Toronto, Department of Chemistry (Canada); Li Dongqing, E-mail: dongqing@mme.uwaterloo.ca [University of Waterloo, Department of Mechanical and Mechatronics Engineering (Canada)

    2013-04-15

    Nanoparticle transport to the opening of the single nanopore created on the cell membrane during the electroporation is studied. First, the permeabilization of a single cell located in a microchannel is investigated. When the nanopores are created, the transport of the nanoparticles from the surrounding liquid to the opening of one of the created nanopores is examined. It was found that the negatively charged nanoparticles preferably move into the nanopores from the side of the cell membrane that faces the negative electrode. Opposite to the electro-osmotic flow effect, the electrophoretic force tends to draw the negatively charged nanoparticles into the opening of the nanopores. The effect of the Brownian force is negligible in comparison with the electro-osmosis and the electrophoresis. Smaller nanoparticles with stronger surface charge transport more easily to the opening of the nanopores. Positively charged nanoparticles preferably enter the nanopores from the side of the cell membrane that faces the positive electrode. On this side, both the electrophoretic and the electro-osmotic forces are in the same directions and contribute to bring the positively charged particles into the nanopores.

  9. Ion selection of charge-modified large nanopores in a graphene sheet

    Science.gov (United States)

    Zhao, Shijun; Xue, Jianming; Kang, Wei

    2013-09-01

    Water desalination becomes an increasingly important approach for clean water supply to meet the rapidly growing demand of population boost, industrialization, and urbanization. The main challenge in current desalination technologies lies in the reduction of energy consumption and economic costs. Here, we propose to use charged nanopores drilled in a graphene sheet as ion exchange membranes to promote the efficiency and capacity of desalination systems. Using molecular dynamics simulations, we investigate the selective ion transport behavior of electric-field-driven KCl electrolyte solution through charge modified graphene nanopores. Our results reveal that the presence of negative charges at the edge of graphene nanopore can remarkably impede the passage of Cl- while enhance the transport of K+, which is an indication of ion selectivity for electrolytes. We further demonstrate that this selectivity is dependent on the pore size and total charge number assigned at the nanopore edge. By adjusting the nanopore diameter and electric charge on the graphene nanopore, a nearly complete rejection of Cl- can be realized. The electrical resistance of nanoporous graphene, which is a key parameter to evaluate the performance of ion exchange membranes, is found two orders of magnitude lower than commercially used membranes. Our results thus suggest that graphene nanopores are promising candidates to be used in electrodialysis technology for water desalinations with a high permselectivity.

  10. Physical Model for Rapid and Accurate Determination of Nanopore Size via Conductance Measurement.

    Science.gov (United States)

    Wen, Chenyu; Zhang, Zhen; Zhang, Shi-Li

    2017-10-27

    Nanopores have been explored for various biochemical and nanoparticle analyses, primarily via characterizing the ionic current through the pores. At present, however, size determination for solid-state nanopores is experimentally tedious and theoretically unaccountable. Here, we establish a physical model by introducing an effective transport length, L eff , that measures, for a symmetric nanopore, twice the distance from the center of the nanopore where the electric field is the highest to the point along the nanopore axis where the electric field falls to e -1 of this maximum. By [Formula: see text], a simple expression S 0 = f (G, σ, h, β) is derived to algebraically correlate minimum nanopore cross-section area S 0 to nanopore conductance G, electrolyte conductivity σ, and membrane thickness h with β to denote pore shape that is determined by the pore fabrication technique. The model agrees excellently with experimental results for nanopores in graphene, single-layer MoS 2 , and ultrathin SiN x films. The generality of the model is verified by applying it to micrometer-size pores.

  11. Solid-state nanopores for scanning single molecules and mimicking biology

    NARCIS (Netherlands)

    Kowalczyk, S.W.

    2011-01-01

    Solid-state nanopores, nanometer-size holes in a thin synthetic membrane, are a versatile tool for the detection and manipulation of charged biomolecules. This thesis describes mostly experimental work on DNA translocation through solid-state nanopores, which we study at the single-molecule level.

  12. Fabrication of Low Noise Borosilicate Glass Nanopores for Single Molecule Sensing.

    Directory of Open Access Journals (Sweden)

    Jayesh A Bafna

    Full Text Available We show low-cost fabrication and characterization of borosilicate glass nanopores for single molecule sensing. Nanopores with diameters of ~100 nm were fabricated in borosilicate glass capillaries using laser assisted glass puller. We further achieve controlled reduction and nanometer-size control in pore diameter by sculpting them under constant electron beam exposure. We successfully fabricate pore diameters down to 6 nm. We next show electrical characterization and low-noise behavior of these borosilicate nanopores and compare their taper geometries. We show, for the first time, a comprehensive characterization of glass nanopore conductance across six-orders of magnitude (1M-1μM of salt conditions, highlighting the role of buffer conditions. Finally, we demonstrate single molecule sensing capabilities of these devices with real-time translocation experiments of individual λ-DNA molecules. We observe distinct current blockage signatures of linear as well as folded DNA molecules as they undergo voltage-driven translocation through the glass nanopores. We find increased signal to noise for single molecule detection for higher trans-nanopore driving voltages. We propose these nanopores will expand the realm of applications for nanopore platform.

  13. BIOLOGICAL NANOPORES FOR BIOPOLYMER SENSING AND SEQUENCING BASED ON FRAC ACTINOPORIN

    NARCIS (Netherlands)

    Maglia, Giovanni; Wloka, Carsten; Mutter, Natalie Lisa; Soskine, Misha; Huang, Gang

    2018-01-01

    The invention relates generally to the field of nanopores and the use thereof in various applications, such as analysis of biopolymer s and macromolecules, typically by making electrical measurements during translocation through a nanopores. Provided is a system comprising a funnel- shaped

  14. Where bio meets nano: The many uses for nanoporous aluminium oxide in biotechnology

    NARCIS (Netherlands)

    Ingham, C.J.; Maat, ter J.; Vos, de W.M.

    2012-01-01

    Porous aluminum oxide (PAO) is a ceramic formed by an anodization process of pure aluminum that enables the controllable assembly of exceptionally dense and regular nanopores in a planar membrane. As a consequence, PAO has a high porosity, nanopores with high aspect ratio, biocompatibility and the

  15. Research Update: Triblock copolymers as templates to synthesize inorganic nanoporous materials

    OpenAIRE

    Yunqi Li; Bishnu Prasad Bastakoti; Yusuke Yamauchi

    2016-01-01

    This review focuses on the application of triblock copolymers as designed templates to synthesize nanoporous materials with various compositions. Asymmetric triblock copolymers have several advantages compared with symmetric triblock copolymers and diblock copolymers, because the presence of three distinct domains can provide more functional features to direct the resultant nanoporous materials. Here we clearly describe significant contributions of asymmetric triblock copolymers, especially p...

  16. Electrochemistry at the edge of a single graphene layer in a nanopore

    DEFF Research Database (Denmark)

    Banerjee, Sutanuka; Shim, Jeong; Rivera, J.

    2013-01-01

    We study the electrochemistry of single layer graphene edges using a nanopore-based structure consisting of stacked graphene and AlO dielectric layers. Nanopores, with diameters ranging from 5 to 20 nm, are formed by an electron beam sculpting process on the stacked layers. This leads to a unique...

  17. Nanoporous Ni with High Surface Area for Potential Hydrogen Storage Application.

    Science.gov (United States)

    Zhou, Xiaocao; Zhao, Haibo; Fu, Zhibing; Qu, Jing; Zhong, Minglong; Yang, Xi; Yi, Yong; Wang, Chaoyang

    2018-06-01

    Nanoporous metals with considerable specific surface areas and hierarchical pore structures exhibit promising applications in the field of hydrogen storage, electrocatalysis, and fuel cells. In this manuscript, a facile method is demonstrated for fabricating nanoporous Ni with a high surface area by using SiO₂ aerogel as a template, i.e., electroless plating of Ni into an SiO₂ aerogel template followed by removal of the template at moderate conditions. The effects of the prepared conditions, including the electroless plating time, temperature of the structure, and the magnetism of nanoporous Ni are investigated in detail. The resultant optimum nanoporous Ni with a special 3D flower-like structure exhibited a high specific surface area of about 120.5 m²/g. The special nanoporous Ni exhibited a promising prospect in the field of hydrogen storage, with a hydrogen capacity of 0.45 wt % on 4.5 MPa at room temperature.

  18. Microtome Sliced Block Copolymers and Nanoporous Polymers as Masks for Nanolithography

    DEFF Research Database (Denmark)

    Shvets, Violetta; Schulte, Lars; Ndoni, Sokol

    2014-01-01

    Introduction. Block copolymers self-assembling properties are commonly used for creation of very fine nanostructures [1]. Goal of our project is to test new methods of the block-copolymer lithography mask preparation: macroscopic pieces of block-copolymers or nanoporous polymers with cross...... PDMS can be chemically etched from the PB matrix by tetrabutylammonium fluoride in tetrahydrofuran and macroscopic nanoporous PB piece is obtained. Both block-copolymer piece and nanoporous polymer piece were sliced with cryomicrotome perpendicular to the axis of cylinder alignment and flakes...... of etching patterns appear only under the certain parts of thick flakes and are not continuous. Although flakes from block copolymer are thinner and more uniform in thickness than flakes from nanoporous polymer, quality of patterns under nanoporous flakes appeared to be better than under block copolymer...

  19. A novel input-parasitic compensation technique for a nanopore-based CMOS DNA detection sensor

    Science.gov (United States)

    Kim, Jungsuk

    2016-12-01

    This paper presents a novel input-parasitic compensation (IPC) technique for a nanopore-based complementary metal-oxide-semiconductor (CMOS) DNA detection sensor. A resistive-feedback transimpedance amplifier is typically adopted as the headstage of a DNA detection sensor to amplify the minute ionic currents generated from a nanopore and convert them to a readable voltage range for digitization. But, parasitic capacitances arising from the headstage input and the nanopore often cause headstage saturation during nanopore sensing, thereby resulting in significant DNA data loss. To compensate for the unwanted saturation, in this work, we propose an area-efficient and automated IPC technique, customized for a low-noise DNA detection sensor, fabricated using a 0.35- μm CMOS process; we demonstrated this prototype in a benchtop test using an α-hemolysin ( α-HL) protein nanopore.

  20. Electro-osmotic flow through nanopores in thin and ultrathin membranes

    Science.gov (United States)

    Melnikov, Dmitriy V.; Hulings, Zachery K.; Gracheva, Maria E.

    2017-06-01

    We theoretically study how the electro-osmotic fluid velocity in a charged cylindrical nanopore in a thin solid state membrane depends on the pore's geometry, membrane charge, and electrolyte concentration. We find that when the pore's length is comparable to its diameter, the velocity profile develops a concave shape with a minimum along the pore axis unlike the situation in very long nanopores with a maximum velocity along the central pore axis. This effect is attributed to the induced pressure along the nanopore axis due to the fluid flow expansion and contraction near the exit or entrance to the pore and to the reduction of electric field inside the nanopore. The induced pressure is maximal when the pore's length is about equal to its diameter while decreasing for both longer and shorter nanopores. A model for the fluid velocity incorporating these effects is developed and shown to be in a good agreement with numerically computed results.

  1. Lithography-based fabrication of nanopore arrays in freestanding SiN and graphene membranes

    Science.gov (United States)

    Verschueren, Daniel V.; Yang, Wayne; Dekker, Cees

    2018-04-01

    We report a simple and scalable technique for the fabrication of nanopore arrays on freestanding SiN and graphene membranes based on electron-beam lithography and reactive ion etching. By controlling the dose of the single-shot electron-beam exposure, circular nanopores of any size down to 16 nm in diameter can be fabricated in both materials at high accuracy and precision. We demonstrate the sensing capabilities of these nanopores by translocating dsDNA through pores fabricated using this method, and find signal-to-noise characteristics on par with transmission-electron-microscope-drilled nanopores. This versatile lithography-based approach allows for the high-throughput manufacturing of nanopores and can in principle be used on any substrate, in particular membranes made out of transferable two-dimensional materials.

  2. Single-Molecule Sensing with Nanopore Confinement: from Chemical Reactions to Biological Interactions.

    Science.gov (United States)

    Lin, Yao; Ying, Yi-Lun; Gao, Rui; Long, Yi-Tao

    2018-03-25

    The nanopore can generate an electrochemical confinement for single-molecule sensing which help understand the fundamental chemical principle in nanoscale dimensions. By observing the generated ionic current, individual bond-making and bond-breaking steps, single biomolecule dynamic conformational changes and electron transfer processes that occur within pore can be monitored with high temporal and current resolution. These single-molecule studies in nanopore confinement are revealing information about the fundamental chemical and biological processes that cannot be extracted from ensemble measurements. In this concept, we introduce and discuss the electrochemical confinement effects on single-molecule covalent reactions, conformational dynamics of individual molecules and host-guest interactions in protein nanopores. Then, we extend the concept of nanopore confinement effects to confine electrochemical redox reactions in solid-state nanopores for developing new sensing mechanisms. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Mechanical Properties of Nanoporous Au: From Empirical Evidence to Phenomenological Modeling

    Directory of Open Access Journals (Sweden)

    Giorgio Pia

    2015-09-01

    Full Text Available The present work focuses on the development of a theoretical model aimed at relating the mechanical properties of nanoporous metals to the bending response of thick ligaments. The model describes the structure of nanoporous metal foams in terms of an idealized regular lattice of massive cubic nodes and thick ligaments with square cross-sections. Following a general introduction to the subject, model predictions are compared with Young’s modulus and the yield strength of nanoporous Au foams determined experimentally and available in literature. It is shown that the model provides a quantitative description of the elastic and plastic deformation behavior of nanoporous metals, reproducing to a satisfactory extent the experimental Young’s modulus and yield strength values of nanoporous Au.

  4. Temperature-dependent photoluminescence and mechanism of CdS thin film grown on Si nanoporous pillar array

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Ling Ling [Department of Physics and Laboratory of Material Physics, Zhengzhou University, Zhengzhou 450052 (China); College of Physics and Chemistry, Henan Polytechnic University, Jiaozuo 454000 (China); Li, Yan Tao [Department of Physics and Laboratory of Material Physics, Zhengzhou University, Zhengzhou 450052 (China); School of Material Science and Engineering, Henan University of Technology, Zhengzhou 454052 (China); Hu, Chu Xiong [Department of Physics and Laboratory of Material Physics, Zhengzhou University, Zhengzhou 450052 (China); Li, Xin Jian, E-mail: lixj@zzu.edu.cn [Department of Physics and Laboratory of Material Physics, Zhengzhou University, Zhengzhou 450052 (China)

    2015-09-15

    Highlights: • CdS/silicon nanoporous pillar array (CdS/Si-NPA) was prepared by a CBD method. • The PL spectrum of CdS/Si-NPA was measured at different temperatures, from 10 to 300 K. • The PL spectrum was composed of four emission bands, obeying different mechanisms. • The PL degradation with temperature was due to phonon-induced escape of carriers. - Abstract: Si-based cadmium sulfide (CdS) is a prospective semiconductor system in constructing optoelectronic nanodevices, and this makes the study on the factors which may affect its optical and electrical properties be of special importance. Here we report that CdS thin film was grown on Si nanoporous pillar array (Si-NPA) by a chemical bath deposition method, and the luminescent properties of CdS/Si-NPA as well as its mechanism were studied by measuring and analyzing its temperature-dependent photoluminescence (PL) spectrum. The low-temperature measurement disclosed that the PL spectrum of CdS/Si-NPA could be decomposed into four emission bands, a blue band, a green band, a red band and an infrared band. The blue band was due to the luminescence from Si-NPA substrate, and the others originate from the CdS thin film. With temperature increasing, the peak energy, PL intensity and peak profile shape for the PL bands from CdS evolves differently. Through theoretical and fitting analyses, the origins of the green, red and infrared band are attributed to the near band-edge emission, the radiative recombination from surface defects to Cd vacancies and those to S interstitials, respectively. The cause of PL degradation is due to the thermal quenching process, a phonon-induced electron escape but with different activation energies. These results might provide useful information for optimizing the preparing parameters to promote the performance of Si-based CdS optoelectronic devices.

  5. Role of aluminum doping on phase transformations in nanoporous titania anodic oxides

    Energy Technology Data Exchange (ETDEWEB)

    Bayata, Fatma [Istanbul Bilgi University, Department of Mechanical Engineering, 34060, Eyup, Istanbul (Turkey); Ürgen, Mustafa, E-mail: urgen@itu.edu.tr [Istanbul Technical University, Department of Metallurgical and Materials Engineering, 34469, Maslak, Istanbul (Turkey)

    2015-10-15

    The role of aluminium doping on anatase to rutile phase transformation of nanoporous titanium oxide films were investigated. For this purpose pure and aluminum doped metal films were deposited on alumina substrates by cathodic arc physical deposition. The nanoporous anodic oxides were prepared by porous anodizing of pure and aluminum doped titanium metallic films in an ethylene glycol + NH{sub 4}F based electrolyte. Nanoporous amorphous structures with 60–80 nm diameter and 2–4 μm length were formed on the surfaces of alumina substrates. The amorphous undoped and Al-doped TiO{sub 2} anodic oxides were heat-treated at different temperatures in the range of 280–720 °C for the investigation of their crystallization behavior. The combined effects of nanoporous structure and Al doping on crystallization behavior of titania were investigated using X-ray diffraction (XRD) and micro Raman analysis. The results indicated that both Al ions incorporated into the TiO{sub 2} structure and the nanoporous structure retarded the rutile formation. It was also revealed that presence or absence of metallic film underneath the nanopores has a major contribution to anatase-rutile transformation. - Highlights: • Al-doped TiO{sub 2} nanopores were grown on alumina substrates using anodization method. • The crystallization behavior of nanoporous Al-doped TiO{sub 2} were investigated. • Al doping into nanoporous TiO{sub 2} retarded the anatase-rutile transformation. • Nanostructuring has significant role in controlling rutile formation temperature. • The absence of the metallic film under the nanopores delayed the rutile formation.

  6. Low-stress silicon nitride layers for MEMS applications

    Science.gov (United States)

    Iliescu, Ciprian; Wei, Jiashen; Chen, Bangtao; Ong, Poh Lam; Tay, Francis E. H.

    2006-12-01

    The paper presents two deposition methods for generation of SiN x layers with "zero" residual stress in PECVD reactors: mixed frequency and high power in high frequency mode (13.56 MHz). Traditionally, mix frequency mode is commonly used to produce low stress SiN x layers, which alternatively applies the HF and LF mode. However, due to the low deposition rate of LF mode, the combined deposition rate of mix frequency is quite small in order to produce homogenous SiN x layers. In the second method, a high power which was up to 600 W has been used, may also produce low residual stress (0-20 MPa), with higher deposition rate (250 to 350 nm/min). The higher power not only leads to higher dissociation rates of gases which results in higher deposition rates, but also brings higher N bonding in the SiN x films and higher compressive stress from higher volume expansion of SiN x films, which compensates the tensile stress and produces low residual stress. In addition, the paper investigates the influence of other important parameters which have great impact to the residual stress and deposition rates, such as reactant gases flow rate and pressure. By using the final optimized recipe, masking layer for anisotropic wet etching in KOH and silicon nitride cantilever have been successfully fabricated based on the low stress SiN x layers. Moreover, nanoporous membrane with 400nm pores has also been fabricated and tested for cell culture. By cultivating the mouse D1 mesenchymal stem cells on top of the nanoporous membrane, the results showed that mouse D1 mesenchymal stem cells were able to grow well. This shows that the nanoporous membrane can be used as the platform for interfacing with living cells to become biocapsules for biomolecular separation.

  7. Light Absorption Enhancement of Silicon-Based Photovoltaic Devices with Multiple Bandgap Structures of Porous Silicon

    Directory of Open Access Journals (Sweden)

    Kuen-Hsien Wu

    2015-09-01

    Full Text Available Porous-silicon (PS multi-layered structures with three stacked PS layers of different porosity were prepared on silicon (Si substrates by successively tuning the electrochemical-etching parameters in an anodization process. The three PS layers have different optical bandgap energy and construct a triple-layered PS (TLPS structure with multiple bandgap energy. Photovoltaic devices were fabricated by depositing aluminum electrodes of Schottky contacts on the surfaces of the developed TLPS structures. The TLPS-based devices exhibit broadband photoresponses within the spectrum of the solar irradiation and get high photocurrent for the incident light of a tungsten lamp. The improved spectral responses of devices are owing to the multi-bandgap structures of TLPS, which are designed with a layered configuration analog to a tandem cell for absorbing a wider energy range of the incidental sun light. The large photocurrent is mainly ascribed to an enhanced light-absorption ability as a result of applying nanoporous-Si thin films as the surface layers to absorb the short-wavelength light and to improve the Schottky contacts of devices. Experimental results reveal that the multi-bandgap PS structures produced from electrochemical-etching of Si wafers are potentially promising for development of highly efficient Si-based solar cells.

  8. Silicon: electrochemistry and luminescence

    NARCIS (Netherlands)

    Kooij, Ernst Stefan

    1997-01-01

    The electrochemistry of crystalline and porous silicon and the luminescence from porous silicon has been studied. One chapter deals with a model for the anodic dissolution of silicon in HF solution. In following chapters both the electrochemistry and various ways of generating visible

  9. Plasmonic devices and sensors built from ordered nanoporous materials.

    Energy Technology Data Exchange (ETDEWEB)

    Jacobs, Benjamin W.; Kobayashi, Yoji (University of California, Berkeley); Houk, Ronald J. T.; Allendorf, Mark D.; Long, Jeffrey R. (University of California, Berkeley); Robertson, Ian M. (University of Illinois Urbana-Champaign, Urbana, IL); House, Stephen D. (University of Illinois Urbana-Champaign, Urbana, IL); Graham, Dennis D. (University of Illinois Urbana-Champaign, Urbana, IL); Talin, Albert Alec (National Institute of Standards & Technology, Gaithersburg, MD); Chang, Noel N. (University of Illinois Urbana-Champaign, Urbana, IL); El Gabaly Marquez, Farid

    2009-09-01

    The objective of this project is to lay the foundation for using ordered nanoporous materials known as metal-organic frameworks (MOFs) to create devices and sensors whose properties are determined by the dimensions of the MOF lattice. Our hypothesis is that because of the very short (tens of angstroms) distances between pores within the unit cell of these materials, enhanced electro-optical properties will be obtained when the nanopores are infiltrated to create nanoclusters of metals and other materials. Synthetic methods used to produce metal nanoparticles in disordered templates or in solution typically lead to a distribution of particle sizes. In addition, creation of the smallest clusters, with sizes of a few to tens of atoms, remains very challenging. Nanoporous metal-organic frameworks (MOFs) are a promising solution to these problems, since their long-range crystalline order creates completely uniform pore sizes with potential for both steric and chemical stabilization. We report results of synthetic efforts. First, we describe a systematic investigation of silver nanocluster formation within MOFs using three representative MOF templates. The as-synthesized clusters are spectroscopically consistent with dimensions {le} 1 nm, with a significant fraction existing as Ag{sub 3} clusters, as shown by electron paramagnetic resonance. Importantly, we show conclusively that very rapid TEM-induced MOF degradation leads to agglomeration and stable, easily imaged particles, explaining prior reports of particles larger than MOF pores. These results solve an important riddle concerning MOF-based templates and suggest that heterostructures composed of highly uniform arrays of nanoparticles within MOFs are feasible. Second, a preliminary study of methods to incorporate fulleride (K{sub 3}C{sub 60}) guest molecules within MOF pores that will impart electrical conductivity is described.

  10. Ultrathin nanoporous membranes for insulator-based dielectrophoresis

    Science.gov (United States)

    Mukaibo, Hitomi; Wang, Tonghui; Perez-Gonzalez, Victor H.; Getpreecharsawas, Jirachai; Wurzer, Jack; Lapizco-Encinas, Blanca H.; McGrath, James L.

    2018-06-01

    Insulator-based dielectrophoresis (iDEP) is a simple, scalable mechanism that can be used for directly manipulating particle trajectories in pore-based filtration and separation processes. However, iDEP manipulation of nanoparticles presents unique challenges as the dielectrophoretic force ({F}{{D}{{E}}{{P}}}) exerted on the nanoparticles can easily be overshadowed by opposing kinetic forces. In this study, a molecularly thin, SiN-based nanoporous membrane (NPN) is explored as a breakthrough technology that enhances {F}{{D}{{E}}{{P}}}. By numerically assessing the gradient of the electric field square ({{\

  11. On the stability of surface-confined nanoporous molecular networks

    Energy Technology Data Exchange (ETDEWEB)

    Ghijsens, Elke; Adisoejoso, Jinne, E-mail: Jinne.adisoejoso@chem.kuleuven.be, E-mail: tobe@chem.es.osaka-u.ac.jp, E-mail: Steven.DeFeyter@chem.kuleuven.be; Van Gorp, Hans; Destoop, Iris; Ivasenko, Oleksandr; Van der Auweraer, Mark; De Feyter, Steven, E-mail: Jinne.adisoejoso@chem.kuleuven.be, E-mail: tobe@chem.es.osaka-u.ac.jp, E-mail: Steven.DeFeyter@chem.kuleuven.be [Department of Chemistry, Division of Molecular Imaging and Photonics, KU Leuven—University of Leuven, Celestijnenlaan 200 F, B-3001 Leuven (Belgium); Noguchi, Aya; Tahara, Kazukuni; Tobe, Yoshito, E-mail: Jinne.adisoejoso@chem.kuleuven.be, E-mail: tobe@chem.es.osaka-u.ac.jp, E-mail: Steven.DeFeyter@chem.kuleuven.be [Graduate School of Engineering Science, Division of Frontier Materials Science, Osaka University, Toyonaka, Osaka 560-8531 (Japan)

    2015-03-14

    Self-assembly of molecular building blocks into two-dimensional nanoporous networks has been a topic of broad interest for many years. However, various factors govern the specific outcome of the self-assembly process, and understanding and controlling these are key to successful creation. In this work, the self-assembly of two alkylated dehydrobenzo[12]annulene building blocks was compared at the liquid-solid interface. It turned out that only a small chemical modification within the building blocks resulted in enhanced domain sizes and stability of the porous packing relative to the dense linear packing. Applying a thermodynamic model for phase transition revealed some key aspects for network formation.

  12. Novel insights into nanopore deformation caused by capillary condensation.

    Science.gov (United States)

    Günther, Gerrit; Prass, Johannes; Paris, Oskar; Schoen, Martin

    2008-08-22

    By means of in situ small-angle x-ray diffraction experiments and semi-grand-canonical ensemble Monte Carlo simulations we demonstrate that sorption and condensation of a fluid confined within nanopores is capable of deforming the pore walls. At low pressures the pore is widened due to a repulsive interaction caused by collisions of the fluid molecules with the walls. At capillary condensation the pores contract abruptly on account of attractive fluid-wall interactions whereas for larger pressures they expand again. These features cannot solely be accounted for by effects related to pore-wall curvature but have to be attributed to fluid-wall dispersion forces instead.

  13. Nanoporous network channels from self-assembled triblock copolymer supramolecules.

    Science.gov (United States)

    du Sart, Gerrit Gobius; Vukovic, Ivana; Vukovic, Zorica; Polushkin, Evgeny; Hiekkataipale, Panu; Ruokolainen, Janne; Loos, Katja; ten Brinke, Gerrit

    2011-02-16

    Supramolecular complexes of a poly(tert-butoxystyrene)-block-polystyrene-block-poly(4-vinylpyridine) triblock copolymers and less than stoichiometric amounts of pentadecylphenol (PDP) are shown to self-assemble into a core-shell gyroid morphology with the core channels formed by the hydrogen-bonded P4VP(PDP)complexes. After structure formation, PDP was removed using a simple washing procedure, resulting in well-ordered nanoporous films that were used as templates for nickel plating. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Combustion Synthesis Of Ultralow-density Nanoporous Gold Foams

    Energy Technology Data Exchange (ETDEWEB)

    Tappan, Bruce C [Los Alamos National Laboratory; Mueller, Alex H [Los Alamos National Laboratory; Steiner, Stephen A [Los Alamos National Laboratory; Luther, Erik P [Los Alamos National Laboratory

    2008-01-01

    A new synthetic pathway for producing nanoporous gold monoliths through combustion synthesis from Au bistetrazoJeamine complexes has been demonstrated. Applications of interest for Au nanofoams include new substrates for nanoparticle-mediated catalysis, embedded antennas, and spectroscopy. Integrated support-and-catalystin-one nanocomposites prepared through combustion synthesis of mixed AuBTA/metal oxide pellets would also be an interesting technology approach for low-cost in-line catalytic conversion media. Furthermore, we envision preparation of ultrahigh surface area gold electrodes for application in electrochemical devices through this method.

  15. Plasmonic resonance of colloidal silver in nanoporous matrix

    International Nuclear Information System (INIS)

    Andreeva, O V; Saitov, S V; Andreeva, N V; Sidorov, A I

    2014-01-01

    The object of the study in this paper – silver nanoporous silicate matrix with pore size less than 20 nm. Colloidal silver particles with volume concentration about 10 −4 are formed within free volume of pores of silicate matrix by chemical method. Changes in the attenuation spectra of the investigated object during changing of the refractive index of free volume of pores from 1.0 to 1.5 are reviewed. Comparison of the obtained experimental data with the results of calculations was carried out

  16. Silicon heterojunction transistor

    International Nuclear Information System (INIS)

    Matsushita, T.; Oh-uchi, N.; Hayashi, H.; Yamoto, H.

    1979-01-01

    SIPOS (Semi-insulating polycrystalline silicon) which is used as a surface passivation layer for highly reliable silicon devices constitutes a good heterojunction for silicon. P- or B-doped SIPOS has been used as the emitter material of a heterojunction transistor with the base and collector of silicon. An npn SIPOS-Si heterojunction transistor showing 50 times the current gain of an npn silicon homojunction transistor has been realized by high-temperature treatments in nitrogen and low-temperature annealing in hydrogen or forming gas

  17. The chemistry of silicon

    CERN Document Server

    Rochow, E G; Emeléus, H J; Nyholm, Ronald

    1975-01-01

    Pergamon Texts in Organic Chemistry, Volume 9: The Chemistry of Silicon presents information essential in understanding the chemical properties of silicon. The book first covers the fundamental aspects of silicon, such as its nuclear, physical, and chemical properties. The text also details the history of silicon, its occurrence and distribution, and applications. Next, the selection enumerates the compounds and complexes of silicon, along with organosilicon compounds. The text will be of great interest to chemists and chemical engineers. Other researchers working on research study involving s

  18. Silicon Microspheres Photonics

    International Nuclear Information System (INIS)

    Serpenguzel, A.

    2008-01-01

    Electrophotonic integrated circuits (EPICs), or alternatively, optoelectronic integrated circuit (OEICs) are the natural evolution of the microelectronic integrated circuit (IC) with the addition of photonic capabilities. Traditionally, the IC industry has been based on group IV silicon, whereas the photonics industry on group III-V semiconductors. However, silicon based photonic microdevices have been making strands in siliconizing photonics. Silicon microspheres with their high quality factor whispering gallery modes (WGMs), are ideal candidates for wavelength division multiplexing (WDM) applications in the standard near-infrared communication bands. In this work, we will discuss the possibility of using silicon microspheres for photonics applications in the near-infrared

  19. Electro-elastoviscous response of polyaniline functionalized nano-porous zeolite based colloidal dispersions.

    Science.gov (United States)

    Chattopadhyay, Ankur; Rani, Poonam; Srivastava, Rajendra; Dhar, Purbarun

    2018-06-01

    The present article discusses the typical influence of grafted conducting polymers in the mesoscale pores of dielectric particles on the static and dynamic electrorheology and electro-viscoelastic behavior of corresponding colloids. Nanocrystalline meso-nanoporous zeolite has been prepared by chemical synthesis and subsequently polyaniline (PANI) coating has been implemented. Electrorheological (ER) suspensions have been formed by dispersing the nanoparticles in silicone oil and their viscoelastic behaviors are examined to understand the nature of such complex colloidal systems under electric fields. PANI-Zeolite ER fluids demonstrate higher static electroviscous effects and yield stress potential than untreated Zeolite, typically studied in literature. Transient electro-viscous characterizations show a stable and negligible hysteresis behavior when both the fluids are exposed to constant as well as time varying electric field intensities. Further oscillatory shear experiments of frequency and strain sweeps exhibit predominant elastic behavior in case of Zeolite based ER suspensions as compared to PANI systems. Detailed investigations reveal Zeolite based ER suspensions display enhanced relative yielding as well as electro-viscoelastic stability than the PANI-Zeolite. The steady state viscous behaviors are scaled against the non-dimensional Mason number to model the system behavior for both fluids. Experimental data of flow behaviors of both the ER fluids are compared with semi-classical models and it is found that the CCJ model possesses a closer proximity than traditional Bingham model, thereby revealing the fluids to be generic pseudo-linear fluids. The present article reveals that while the PANI based fluids are typically hailed superior in literature, it is only restricted to steady shear utilities. In case of dynamic and oscillatory systems, the traditional Zeolite based fluids exhibit superior ER caliber. Copyright © 2018 Elsevier Inc. All rights reserved.

  20. PS-b-PMMA/PLA blends for nanoporous templates with hierarchical and tunable pore size

    Science.gov (United States)

    Nguyen, Thi-Hoa; Vayer, Marylène; Sinturel, Christophe

    2018-01-01

    Blends of poly(styrene)-block-poly(methyl methacrylate) (PS-b-PMMA) and poly(lactide) (PLA) were deposited in the form of thin films on the surface of modified silicon wafers and exposed to tetrahydrofuran (THF) vapor annealing. It was shown that in specific experimental conditions, a core-shell morphology consisting in cylinders with a PMMA shell and a PLA core, within a continuous matrix of PS, was formed. In this case, PLA naturally segregated in the core of the PMMA cylinders, minimizing the PS/PLA interaction, which constitutes the most incompatible pair (the interaction strength between the various components was confirmed in thin films of the corresponding polymer blends). Compared to other block copolymer/homopolymer blends described in the literature, this system exhibits unexpected high increase of the characteristic lengths of the system (center-to-center distance and diameter). This was attributed to a partial solubilization of the PLA in the PMMA corona (the two polymers are highly compatible), inducing an enhanced level of PS and PLA stretching caused by the strong repulsion between these two polymers. The selective extraction of the PLA yielded to porous domains with small dimensions (6 ± 2.5 nm), reaching the performances that are currently attained in highly incompatible block polymers with low molecular weight. Further PMMA removal revealed a second porosity level, with higher pores diameter and center-to-center distance compared to the neat PS-b-PMMA system. This work highlights how PS-b-PMMA, that currently represents one of the industrial standards nanoporous template precursors, can be modified in an easy and costless approach using PLA homopolymer addition.

  1. Basic evaluation of typical nanoporous silica nanoparticles in being drug carrier: Structure, wettability and hemolysis.

    Science.gov (United States)

    Li, Jing; Guo, Yingyu

    2017-04-01

    Herein, the present work devoted to study the basic capacity of nanoporous silica nanoparticles in being drug carrier that covered structure, wettability and hemolysis so as to provide crucial evaluation. Typical nanoporous silica nanoparticles that consist of nanoporous silica nanoparticles (NSN), amino modified nanoporous silica nanoparticles (amino-NSN), carboxyl modified nanoporous silica nanoparticles (carboxyl-NSN) and hierachical nanoporous silica nanoparticles (hierachical-NSN) were studied. The results showed that their wettability and hemolysis were closely related to structure and surface modification. Basically, wettability became stronger as the amount of OH on the surface of NSN was higher. Both large nanopores and surface modification can reduce the wettability of NSN. Furthermore, NSN series were safe to be used when they circulated into the blood in low concentration, while if high concentration can not be avoided during administration, high porosity or amino modification of NSN were safer to be considered. It is believed that the basic evaluation of NSN can make contribution in providing scientific instruction for designing drug loaded NSN systems. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Precise fabrication of a 5 nm graphene nanopore with a helium ion microscope for biomolecule detection

    Science.gov (United States)

    Deng, Yunsheng; Huang, Qimeng; Zhao, Yue; Zhou, Daming; Ying, Cuifeng; Wang, Deqiang

    2017-01-01

    We report a scalable method to fabricate high-quality graphene nanopores for biomolecule detection using a helium ion microscope (HIM). HIM milling shows promising capabilities for precisely controlling the size and shape, and may allow for the potential production of nanopores at wafer scale. Nanopores could be fabricated at different sizes ranging from 5 to 30 nm in diameter in few minutes. Compared with the current solid-state nanopore fabrication techniques, e.g. transmission electron microscopy, HIM is fast. Furthermore, we investigated the exposure-time dependence of graphene nanopore formation: the rate of pore expansion did not follow a simple linear relationship with exposure time, but a fast expansion rate at short exposure time and a slow rate at long exposure time. In addition, we performed biomolecule detection with our patterned graphene nanopore. The ionic current signals induced by 20-base single-stranded DNA homopolymers could be used as a basis for homopolymer differentiation. However, the charge interaction of homopolymer chains with graphene nanopores, and the conformations of homopolymer chains need to be further considered to improve the accuracy of discrimination.

  3. Biomimetic Mineralization of Gold Nanoclusters as Multifunctional Thin Films for Glass Nanopore Modification, Characterization, and Sensing.

    Science.gov (United States)

    Cao, Sumei; Ding, Shushu; Liu, Yingzi; Zhu, Anwei; Shi, Guoyue

    2017-08-01

    Hurdles of nanopore modification and characterization restrain the development of glass capillary-based nanopore sensing platforms. In this article, a simple but effective biomimetic mineralization method was developed to decorate glass nanopore with a thin film of bovine serum albumin-protected Au nanocluster (BSA-Au NC). The BSA-Au NC film emitted a strong red fluorescence whereby nondestructive characterization of Au film decorated at the inner surface of glass nanopore can be facilely achieved by a fluorescence microscopy. Besides, the BSA molecules played dual roles in the fabrication of functionalized Au thin film in glass nanopore: they not only directed the synthesis of fluorescent Au thin film but also provided binding sites for recognition, thus achieving synthesis-modification integration. This occurred due to the ionized carboxyl groups (-COO - ) of a BSA coating layer on Au NCs which can interacted with arginine (Arg) via guanidinium groups. The added Arg selectively led to the change in the charge and ionic current of BSA-Au NC film-decorated glass nanopore. Such ionic current responses can be used for quantifying Arg with a detection limit down to 1 fM, which was more sensitive than that of previous sensing systems. Together, the designed method exhibited great promise in providing a facile and controllable solution for glass nanopore modification, characterization, and sensing.

  4. In vitro extracellular recording and stimulation performance of nanoporous gold-modified multi-electrode arrays

    Science.gov (United States)

    Kim, Yong Hee; Kim, Gook Hwa; Kim, Ah Young; Han, Young Hwan; Chung, Myung-Ae; Jung, Sang-Don

    2015-12-01

    Objective. Nanoporous gold (Au) structures can reduce the impedance and enhance the charge injection capability of multi-electrode arrays (MEAs) used for interfacing neuronal networks. Even though there are various nanoporous Au preparation techniques, fabrication of MEA based on low-cost electro-codeposition of Ag:Au has not been performed. In this work, we have modified a Au MEA via the electro-codeposition of Ag:Au alloy, followed by the chemical etching of Ag, and report on the in vitro extracellular recording and stimulation performance of the nanoporous Au-modified MEA. Approach. Ag:Au alloy was electro-codeposited on a bilayer lift-off resist sputter-deposition passivated Au MEA followed by chemical etching of Ag to form a porous Au structure. Main results. The porous Au structure was analyzed by scanning electron microscopy and tunneling electron microscopy and found to have an interconnected nanoporous Au structure. The impedance value of the nanoporous Au-modified MEA is 15.4 ± 0.55 kΩ at 1 kHz, accompanied by the base noise V rms of 2.4 ± 0.3 μV. The charge injection limit of the nanoporous Au-modified electrode estimated from voltage transient measurement is approximately 1 mC cm-2, which is comparable to roughened platinum and carbon nanotube electrodes. The charge injection capability of the nanoporous Au-modified MEA was confirmed by observing stimulus-induced spikes at above 0.2 V. The nanoporous Au-modified MEA showed mechanical durability upon ultrasonic treatment for up to an hour. Significance. Electro-codeposition of Ag:Au alloy combined with chemical etching Ag is a low-cost process for fabricating nanoporous Au-modified MEA suitable for establishing the stimulus-response relationship of cultured neuronal networks.

  5. In vitro extracellular recording and stimulation performance of nanoporous gold-modified multi-electrode arrays.

    Science.gov (United States)

    Kim, Yong Hee; Kim, Gook Hwa; Kim, Ah Young; Han, Young Hwan; Chung, Myung-Ae; Jung, Sang-Don

    2015-12-01

    Nanoporous gold (Au) structures can reduce the impedance and enhance the charge injection capability of multi-electrode arrays (MEAs) used for interfacing neuronal networks. Even though there are various nanoporous Au preparation techniques, fabrication of MEA based on low-cost electro-codeposition of Ag:Au has not been performed. In this work, we have modified a Au MEA via the electro-codeposition of Ag:Au alloy, followed by the chemical etching of Ag, and report on the in vitro extracellular recording and stimulation performance of the nanoporous Au-modified MEA. Ag:Au alloy was electro-codeposited on a bilayer lift-off resist sputter-deposition passivated Au MEA followed by chemical etching of Ag to form a porous Au structure. The porous Au structure was analyzed by scanning electron microscopy and tunneling electron microscopy and found to have an interconnected nanoporous Au structure. The impedance value of the nanoporous Au-modified MEA is 15.4 ± 0.55 kΩ at 1 kHz, accompanied by the base noise V rms of 2.4 ± 0.3 μV. The charge injection limit of the nanoporous Au-modified electrode estimated from voltage transient measurement is approximately 1 mC cm(-2), which is comparable to roughened platinum and carbon nanotube electrodes. The charge injection capability of the nanoporous Au-modified MEA was confirmed by observing stimulus-induced spikes at above 0.2 V. The nanoporous Au-modified MEA showed mechanical durability upon ultrasonic treatment for up to an hour. Electro-codeposition of Ag:Au alloy combined with chemical etching Ag is a low-cost process for fabricating nanoporous Au-modified MEA suitable for establishing the stimulus-response relationship of cultured neuronal networks.

  6. Porous silicon powder as an adsorbent of heavy metal (nickel)

    Science.gov (United States)

    Nabil, Marwa; Motaweh, Hussien A.

    2018-04-01

    New and inexpensive nanoporous silicon (NPS) powder was prepared by alkali chemical etching using sonication technique and was subsequently investigated as an adsorbent in batch systems for the adsorption Ni(II) ions in an aqueous solution. The optimum conditions for the Ni(II) ion adsorption capacity of the NPS powder were studied in detail by varying parameters such as the initial Ni(II) concentration, the solution pH value, the adsorption temperature and contact time. The results indicated that the maximum adsorption capacity and the maximum removal percent of Ni(II) reached 2665.33 mg/g and 82.6%, respectively, at an initial Ni(II) concentration of 100 mg/L, adsorption time of 30 min and no effect of the solution pH and adsorption temperature.

  7. Multiscale Morphology of Nanoporous Copper Made from Intermetallic Phases

    International Nuclear Information System (INIS)

    Egle, Tobias; Harvard University, Cambridge, MA; Barroo, Cédric; Janvelyan, Nare; Baumgaertel, Andreas C.

    2017-01-01

    Many application-relevant properties of nanoporous metals critically depend on their multiscale architecture. For example, the intrinsically high step-edge density of curved surfaces at the nanoscale provides highly reactive sites for catalysis, whereas the macroscale pore and grain morphology determines the macroscopic properties, such as mass transport, electrical conductivity, or mechanical properties. Here, in this work, we systematically study the effects of alloy composition and dealloying conditions on the multiscale morphology of nanoporous copper (np-Cu) made from various commercial Zn–Cu precursor alloys. Using a combination of X-ray diffraction, electron backscatter diffraction, and focused ion beam cross-sectional analysis, our results reveal that the macroscopic grain structure of the starting alloy surprisingly survives the dealloying process, despite a change in crystal structure from body-centered cubic (Zn–Cu starting alloy) to face-centered cubic (Cu). The nanoscale structure can be controlled by the acid used for dealloying with HCl leading to a larger and more faceted ligament morphology compared to that of H_3PO_4. Finally, anhydrous ethanol dehydrogenation was used as a probe reaction to test the effect of the nanoscale ligament morphology on the apparent activation energy of the reaction.

  8. Nanoporous metal/oxide hybrid electrodes for electrochemical supercapacitors

    Science.gov (United States)

    Lang, Xingyou; Hirata, Akihiko; Fujita, Takeshi; Chen, Mingwei

    2011-04-01

    Electrochemical supercapacitors can deliver high levels of electrical power and offer long operating lifetimes, but their energy storage density is too low for many important applications. Pseudocapacitive transition-metal oxides such as MnO2 could be used to make electrodes in such supercapacitors, because they are predicted to have a high capacitance for storing electrical charge while also being inexpensive and not harmful to the environment. However, the poor conductivity of MnO2 (10-5-10-6 S cm-1) limits the charge/discharge rate for high-power applications. Here, we show that hybrid structures made of nanoporous gold and nanocrystalline MnO2 have enhanced conductivity, resulting in a specific capacitance of the constituent MnO2 (~1,145 F g-1) that is close to the theoretical value. The nanoporous gold allows electron transport through the MnO2, and facilitates fast ion diffusion between the MnO2 and the electrolytes while also acting as a double-layer capacitor. The high specific capacitances and charge/discharge rates offered by such hybrid structures make them promising candidates as electrodes in supercapacitors, combining high-energy storage densities with high levels of power delivery.

  9. Ultrahigh Flux Thin Film Boiling Heat Transfer Through Nanoporous Membranes.

    Science.gov (United States)

    Wang, Qingyang; Chen, Renkun

    2018-05-09

    Phase change heat transfer is fundamentally important for thermal energy conversion and management, such as in electronics with power density over 1 kW/cm 2 . The critical heat flux (CHF) of phase change heat transfer, either evaporation or boiling, is limited by vapor flux from the liquid-vapor interface, known as the upper limit of heat flux. This limit could in theory be greater than 1 kW/cm 2 on a planar surface, but its experimental realization has remained elusive. Here, we utilized nanoporous membranes to realize a new "thin film boiling" regime that resulted in an unprecedentedly high CHF of over 1.2 kW/cm 2 on a planar surface, which is within a factor of 4 of the theoretical limit, and can be increased to a higher value if mechanical strength of the membranes can be improved (demonstrated with 1.85 kW/cm 2 CHF in this work). The liquid supply is achieved through a simple nanoporous membrane that supports the liquid film where its thickness automatically decreases as heat flux increases. The thin film configuration reduces the conductive thermal resistance, leads to high frequency bubble departure, and provides separate liquid-vapor pathways, therefore significantly enhances the heat transfer. Our work provides a new nanostructuring approach to achieve ultrahigh heat flux in phase change heat transfer and will benefit both theoretical understanding and application in thermal management of high power devices of boiling heat transfer.

  10. Electrochemical impedance spectroscopy of nanoporous anodic alumina template

    International Nuclear Information System (INIS)

    Shahzad, K.

    2010-01-01

    Room temperature EIS characterization of nanoporous anodic alumina prepared at 40 V and 60 V has been done in 0.3 M oxalic acid solution. Rapid decrease in impedance was observed for the template prepared at 40 V. EIS study of porous anodic alumina template prepared in 0.3 M oxalic acid has been done in different electrolytes. Templates prepared in 0.3 M sulfuric acid solution were also characterized for comparison. Rapid decrease in the thickness of nonporous anodic film was observed with an increase of aggressiveness of electrolyte. Temperature based systematic study of EIS measurement has been done for porous anodic alumina template at different temperatures. Formation of micropores was observed in the nanoporous anodic alumina film formed on aluminum in 0.3 M oxalic acid solution which accelerates the dissolution rate with increase of measurement temperature. In addition to these, electropolishing behavior of pure aluminum has also been studied in different electrolytes and it was observed that electropolishing conditions prior to anodization are extremely important. (author)

  11. Modeling the self-assembly of ordered nanoporous materials

    Energy Technology Data Exchange (ETDEWEB)

    Monson, Peter [Univ. of Massachusetts, Amherst, MA (United States); Auerbach, Scott [Univ. of Massachusetts, Amherst, MA (United States)

    2017-11-13

    This report describes progress on a collaborative project on the multiscale modeling of the assembly processes in the synthesis of nanoporous materials. Such materials are of enormous importance in modern technology with application in the chemical process industries, biomedicine and biotechnology as well as microelectronics. The project focuses on two important classes of materials: i) microporous crystalline materials, such as zeolites, and ii) ordered mesoporous materials. In the first case the pores are part of the crystalline structure, while in the second the structures are amorphous on the atomistic length scale but where surfactant templating gives rise to order on the length scale of 2 - 20 nm. We have developed a modeling framework that encompasses both these kinds of materials. Our models focus on the assembly of corner sharing silica tetrahedra in the presence of structure directing agents. We emphasize a balance between sufficient realism in the models and computational tractibility given the complex many-body phenomena. We use both on-lattice and off-lattice models and the primary computational tools are Monte Carlo simulations with sampling techniques and ensembles appropriate to specific situations. Our modeling approach is the first to capture silica polymerization, nanopore crystallization, and mesopore formation through computer-simulated self assembly.

  12. Development of electrochemical supercapacitors with uniform nanoporous silver network

    International Nuclear Information System (INIS)

    Li, Rui; Liu, Xiongjun; Wang, Hui; Wu, Yuan; Lu, Z.P.

    2015-01-01

    Metal oxides such as manganese dioxide (MnO 2 ) are often used as electrode materials for supercapacitors due to their high specific capacitance. In practice, however, their specific capacitance is much smaller than the theoretical limit due to the low electrical conductivity and serious agglomeration. In the present work, we demonstrate that highly conductive nanoporous silver (NPS) network with uniform continuous nanoporosity and high surface area which was fabricated by dealloying Ag-Mg-Ca metallic glasses can be employed as supports and collectors for MnO 2 capacitors. By plating the MnO 2 nanocrystals into the nanopore structure, the NPS/MnO 2 composite electrode provides fast ionic conduction and excellent electron-proton transport, resulting in an ultrahigh specific capacitance of the plated active MnO 2 (∼1088 F g −1 ), which is close to the theoretical limit. The unique combination of high specific capacitance and long cycle life enhanced by the current composite structure makes the NPS/MnO 2 composite promising for electrochemical supercapacitor as electrode material. In addition, our findings suggest that the uniform NPS network is capable for improving capacitance performance of metal oxides in electrochemical supercapacitors.

  13. Gas adsorption and capillary condensation in nanoporous alumina films

    Energy Technology Data Exchange (ETDEWEB)

    Casanova, Felix; Chiang, Casey E; Li, Chang-Peng; Roshchin, Igor V; Schuller, Ivan K [Physics Department, University of California-San Diego, La Jolla, CA 92093 (United States); Ruminski, Anne M; Sailor, Michael J [Department of Chemistry and Biochemistry, University of California-San Diego, La Jolla, CA 92093 (United States)], E-mail: casanova@physics.ucsd.edu

    2008-08-06

    Gas adsorption and capillary condensation of organic vapors are studied by optical interferometry, using anodized nanoporous alumina films with controlled geometry (cylindrical pores with diameters in the range of 10-60 nm). The optical response of the film is optimized with respect to the geometric parameters of the pores, for potential performance as a gas sensor device. The average thickness of the adsorbed film at low relative pressures is not affected by the pore size. Capillary evaporation of the liquid from the nanopores occurs at the liquid-vapor equilibrium described by the classical Kelvin equation with a hemispherical meniscus. Due to the almost complete wetting, we can quantitatively describe the condensation for isopropanol using the Cohan model with a cylindrical meniscus in the Kelvin equation. This model describes the observed hysteresis and allows us to use the adsorption branch of the isotherm to calculate the pore size distribution of the sample in good agreement with independent structural measurements. The condensation for toluene lacks reproducibility due to incomplete surface wetting. This exemplifies the relevant role of the fluid-solid (van der Waals) interactions in the hysteretic behavior of capillary condensation.

  14. Gas adsorption and capillary condensation in nanoporous alumina films

    International Nuclear Information System (INIS)

    Casanova, Felix; Chiang, Casey E; Li, Chang-Peng; Roshchin, Igor V; Schuller, Ivan K; Ruminski, Anne M; Sailor, Michael J

    2008-01-01

    Gas adsorption and capillary condensation of organic vapors are studied by optical interferometry, using anodized nanoporous alumina films with controlled geometry (cylindrical pores with diameters in the range of 10-60 nm). The optical response of the film is optimized with respect to the geometric parameters of the pores, for potential performance as a gas sensor device. The average thickness of the adsorbed film at low relative pressures is not affected by the pore size. Capillary evaporation of the liquid from the nanopores occurs at the liquid-vapor equilibrium described by the classical Kelvin equation with a hemispherical meniscus. Due to the almost complete wetting, we can quantitatively describe the condensation for isopropanol using the Cohan model with a cylindrical meniscus in the Kelvin equation. This model describes the observed hysteresis and allows us to use the adsorption branch of the isotherm to calculate the pore size distribution of the sample in good agreement with independent structural measurements. The condensation for toluene lacks reproducibility due to incomplete surface wetting. This exemplifies the relevant role of the fluid-solid (van der Waals) interactions in the hysteretic behavior of capillary condensation

  15. Gas adsorption and capillary condensation in nanoporous alumina films.

    Science.gov (United States)

    Casanova, Fèlix; Chiang, Casey E; Li, Chang-Peng; Roshchin, Igor V; Ruminski, Anne M; Sailor, Michael J; Schuller, Ivan K

    2008-08-06

    Gas adsorption and capillary condensation of organic vapors are studied by optical interferometry, using anodized nanoporous alumina films with controlled geometry (cylindrical pores with diameters in the range of 10-60 nm). The optical response of the film is optimized with respect to the geometric parameters of the pores, for potential performance as a gas sensor device. The average thickness of the adsorbed film at low relative pressures is not affected by the pore size. Capillary evaporation of the liquid from the nanopores occurs at the liquid-vapor equilibrium described by the classical Kelvin equation with a hemispherical meniscus. Due to the almost complete wetting, we can quantitatively describe the condensation for isopropanol using the Cohan model with a cylindrical meniscus in the Kelvin equation. This model describes the observed hysteresis and allows us to use the adsorption branch of the isotherm to calculate the pore size distribution of the sample in good agreement with independent structural measurements. The condensation for toluene lacks reproducibility due to incomplete surface wetting. This exemplifies the relevant role of the fluid-solid (van der Waals) interactions in the hysteretic behavior of capillary condensation.

  16. Combined HRTEM and PEELS analysis of nanoporous and amorphous carbon

    International Nuclear Information System (INIS)

    Peng, J.L.; Fan, X. D.; Bursill, L.A.

    1997-01-01

    Both the mass density (1.37 kgm/m 3 ) and sp 2 +sp 3 bonding fraction (0.15) were determined for an unusual nanoporous amorphous carbon consisting of curved single graphitic sheets. A combination of high-resolution transmission electron microscopy (HRTEM) and parallel electron energy loss spectroscopy (PEELS) was used. The values of these two parameters provide important constraints for the determination of the structure of this relatively low density variety of nanoporous carbon. The results are relevant also in the search for negatively-curved Schwarzite-related carbon structures. New date are also presented for highly-oriented pyrollytic graphite (HOPG), chemically vapour deposited (CVD) diamond, C 60 , glassy carbon (GC) and evaporated amorphous carbon (EAC); these are compared with the results for NAC. Kramers-Kronig analysis (KKA) of the low-loss PEELS data shows that the band gaps of both NAC and EAC are collapsed relative to that of CVD diamond. 18 refs., 2 tabs., 3 figs

  17. Synthesis and characterization of electrical conducting nanoporous carbon structures

    International Nuclear Information System (INIS)

    El Mir, L.; Kraiem, S.; Bengagi, M.; Elaloui, E.; Ouederni, A.; Alaya, S.

    2007-01-01

    Nanoporous organic xerogel compounds were prepared by sol-gel method from pyrogallol-formaldehyde (PF) mixtures in water using perchloric acid as catalyst. The preparation conditions of electrical conducting carbon (ECC) structures were explored by changing the pyrolysis temperature. The effect of this preparation parameters on the structural and electrical properties of the obtained ECCs were studied, respectively, by thermogravimetric analysis (TGA), nitrogen adsorption isotherms, IR spectroscopy and electrical conductivity measurements. The analysis of the obtained results revealed that, the polymeric insulating phase was transformed progressively with pyrolysis temperature into carbon conducting phase; this means the formation of long continuous conducting path for charge carriers when the carbon microparticles inside the structure agglomerated with thermal treatment and the samples exhibited tangible percolation behaviour where the percolation threshold can be determined by pyrolysis temperature. The temperature-dependent conductivity and the I(V) characteristics of the obtained ECC structures show a non-ohmic behaviour. The results obtained from TGA and differential thermal analyser (DTA) thermograms, scanning electron microscope (SEM) and transmission electron microscope (TEM) micrographs, IR spectroscopy and X-ray diffraction revealed that, the obtained ECC structures consist of amorphous and nanoporous electrical conducting carbon materials

  18. Combined HRTEM and PEELS analysis of nanoporous and amorphous carbon

    Energy Technology Data Exchange (ETDEWEB)

    Peng, J.L.; Fan, X. D.; Bursill, L.A.

    1997-06-01

    Both the mass density (1.37 kgm/m{sup 3}) and sp{sup 2}+sp{sup 3} bonding fraction (0.15) were determined for an unusual nanoporous amorphous carbon consisting of curved single graphitic sheets. A combination of high-resolution transmission electron microscopy (HRTEM) and parallel electron energy loss spectroscopy (PEELS) was used. The values of these two parameters provide important constraints for the determination of the structure of this relatively low density variety of nanoporous carbon. The results are relevant also in the search for negatively-curved Schwarzite-related carbon structures. New date are also presented for highly-oriented pyrollytic graphite (HOPG), chemically vapour deposited (CVD) diamond, C{sub 60}, glassy carbon (GC) and evaporated amorphous carbon (EAC); these are compared with the results for NAC. Kramers-Kronig analysis (KKA) of the low-loss PEELS data shows that the band gaps of both NAC and EAC are collapsed relative to that of CVD diamond. 18 refs., 2 tabs., 3 figs.

  19. Fabrication of Polymer Microneedle Electrodes Coated with Nanoporous Parylene

    Science.gov (United States)

    Nishinaka, Yuya; Jun, Rina; Setia Prihandana, Gunawan; Miki, Norihisa

    2013-06-01

    In this study, we demonstrate the fabrication of polymer microneedle electrodes covered with a nanoporous parylene film that can serve as flexible electrodes for a brain-machine interface. In brain wave measurement, the electric impedance of electrodes should be below 10 kΩ at 15 Hz, and the conductive layer needs to be protected to survive its insertion into the stratum corneum. Polymer microneedles can be used as substrates for flexible electrodes, which can compensate for the movement of the skin; however, the adhesion between a conductive metal film, such as a silver film, and a polymer, such as poly(dimethylsiloxane) (PDMS), is weak. Therefore, we coated the electrode surface with a nanoporous parylene film, following the vapor deposition of a silver film. When the porosity of the parylene film is appropriate, it protects the silver film while allowing the electrode to have sufficient conductivity. The porosity can be controlled by adjusting the amount of the parylene dimer used for the deposition or the parylene film thickness. We experimentally verified that a conductive membrane was successfully protected while maintaining a conductivity below 10 kΩ when the thickness of the parylene film was between 25 and 38 nm.

  20. On the anodic aluminium oxide refractive index of nanoporous templates

    International Nuclear Information System (INIS)

    Hierro-Rodriguez, A; Rocha-Rodrigues, P; Araujo, J P; Valdés-Bango, F; Alameda, J M; Teixeira, J M; Jorge, P A S; Santos, J L; Guerreiro, A

    2015-01-01

    In the present study, we have determined the intrinsic refractive index of anodic aluminium oxide, which is originated by the formation of nanoporous alumina templates. Different templates have been fabricated by the conventional two-step anodization procedure in oxalic acid. Their porosities were modified by chemical wet etching allowing the tuning of their effective refractive indexes (air-filled nanopores  +  anodic aluminium oxide). By standard spectroscopic light transmission measurements, the effective refractive index for each different template was extracted in the VIS–NIR region. The determination of the intrinsic anodic aluminium oxide refractive index was performed by using the Maxwell–Garnett homogenization theory. The results are coincident for all the fabricated samples. The obtained refractive index (∼1.55) is quite lower (∼22%) than the commonly used Al 2 O 3 handbook value (∼1.75), showing that the amorphous nature of the anodic oxide structure strongly conditions its optical properties. This difference is critical for the correct design and modeling of optical plasmonic metamaterials based on anodic aluminium oxide nanoporous templates. (paper)

  1. Enhanced microcontact printing of proteins on nanoporous silica surface

    Energy Technology Data Exchange (ETDEWEB)

    Blinka, Ellen; Hu Ye; Gopal, Ashwini; Hoshino, Kazunori; Lin, Kevin; Zhang, John X J [Department of Biomedical Engineering, University of Texas at Austin, Austin, TX 78758 (United States); Loeffler, Kathryn; Liu Xuewu; Ferrari, Mauro, E-mail: John.Zhang@engr.utexas.edu [Department of Nanomedicine and Biomedical Engineering, University of Texas Health Science Service, Houston, TX 77031 (United States)

    2010-10-15

    We demonstrate porous silica surface modification, combined with microcontact printing, as an effective method for enhanced protein patterning and adsorption on arbitrary surfaces. Compared to conventional chemical treatments, this approach offers scalability and long-term device stability without requiring complex chemical activation. Two chemical surface treatments using functionalization with the commonly used 3-aminopropyltriethoxysilane (APTES) and glutaraldehyde (GA) were compared with the nanoporous silica surface on the basis of protein adsorption. The deposited thickness and uniformity of porous silica films were evaluated for fluorescein isothiocyanate (FITC)-labeled rabbit immunoglobulin G (R-IgG) protein printed onto the substrates via patterned polydimethlysiloxane (PDMS) stamps. A more complete transfer of proteins was observed on porous silica substrates compared to chemically functionalized substrates. A comparison of different pore sizes (4-6 nm) and porous silica thicknesses (96-200 nm) indicates that porous silica with 4 nm diameter, 57% porosity and a thickness of 96 nm provided a suitable environment for complete transfer of R-IgG proteins. Both fluorescence microscopy and atomic force microscopy (AFM) were used for protein layer characterizations. A porous silica layer is biocompatible, providing a favorable transfer medium with minimal damage to the proteins. A patterned immunoassay microchip was developed to demonstrate the retained protein function after printing on nanoporous surfaces, which enables printable and robust immunoassay detection for point-of-care applications.

  2. Formation and evolution of nanoporous bimetallic Ag-Cu alloy by electrochemically dealloying Mg-(Ag-Cu)-Y metallic glass

    International Nuclear Information System (INIS)

    Li, Ran; Wu, Na; Liu, Jijuan; Jin, Yu; Chen, Xiao-Bo; Zhang, Tao

    2017-01-01

    Highlights: • Uniform nanoporous Ag-Cu alloy was fabricated by dealloying Mg-based metallic glass. • The nanoporous structure was built up with numerous Ag-Cu ligaments. • The nanoporous ligaments show two-stage coarsening behavior with dealloying time. • The formation and evolution mechanisms of the nanoporous structure were clarified. • It could provide new guidance to the synthesis of nanoporous multi-component alloys. - Abstract: A three-dimensional nanoporous bimetallic Ag-Cu alloy with uniform chemical composition has been fabricated by dealloying Mg_6_5Ag_1_2_._5Cu_1_2_._5Y_1_0 metallic glass in dilute (0.04 M) H_2SO_4 aqueous solution under free-corrosion conditions. The nanoporous Ag-Cu evolves through two distinct stages. First, ligaments of the nanoporous structure, consisting of supersaturated Ag(Cu) solid solution with a constant Ag/Cu mole ratio of 1:1, are yielded. Second, with excessive immersion, some Cu atoms separate from the metastable nanoporous matrix and form spherical Cu particles on the sample surface. Formation and evolution mechanisms of the nanoporous structure are proposed.

  3. Membranes from nanoporous 1D and 2D materials: A review of opportunities, developments, and challenges

    KAUST Repository

    Kim, Wun-gwi; Nair, Sankar

    2013-01-01

    strategies to process these materials into membranes and thin films with high performance. This work provides the first comprehensive review of this emerging area. We first discuss approaches for the synthesis and structural characterization of nanoporous 1D

  4. Nanoporous Insulating Oxide Deionization Device Having Asymmetric Electrodes and Method of Use Thereof

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A nanoporous insulating oxide deionization device, method of manufacture and method of use thereof for deionizing a water supply (such as a hard water supply), for...

  5. Interconnected V2O5 nanoporous network for high-performance supercapacitors.

    Science.gov (United States)

    Saravanakumar, B; Purushothaman, Kamatchi K; Muralidharan, G

    2012-09-26

    Vanadium pentoxide (V(2)O(5)) has attracted attention for supercapcitor applications because of its extensive multifunctional properties. In the present study, V(2)O(5) nanoporous network was synthesized via simple capping-agent-assisted precipitation technique and it is further annealed at different temperatures. The effect of annealing temperature on the morphology, electrochemical and structural properties, and stability upon oxidation-reduction cycling has been analyzed for supercapacitor application. We achieved highest specific capacitance of 316 F g(-1) for interconnected V(2)O(5) nanoporous network. This interconnected nanoporous network creates facile nanochannels for ion diffusion and facilitates the easy accessibility of ions. Moreover, after six hundred consecutive cycling processes the specific capacitance has changed only by 24%. A simple cost-effective preparation technique of V(2)O(5) nanoporous network with excellent capacitive behavior, energy density, and stability encourages its possible commercial exploitation for the development of high-performance supercapacitors.

  6. Engineering of highly ordered TiO2 nanopore arrays by anodization

    Science.gov (United States)

    Wang, Huijie; Huang, Zhennan; Zhang, Li; Ding, Jie; Ma, Zhaoxia; Liu, Yong; Kou, Shengzhong; Yang, Hangsheng

    2016-07-01

    Finite element analysis was used to simulate the current density distributions in the TiO2 barrier layer formed at the initial stage of Ti anodization. The morphology modification of the barrier layer was found to induce current density distribution change. By starting the anodization with proper TiO2 barrier layer morphology, the current density distribution can be adjusted to favor the formation of either nanotube arrays or nanopore arrays of anodic TiO2. We also found that the addition of sodium acetate into the electrolyte suppressed both the field-assisted chemical dissolution of TiO2 and the TiF62- hydrolysis induced TiO2 deposition during anodization, and thus further favored the nanopore formation. Accordingly, highly ordered anodic TiO2 nanopore arrays, similar to anodic aluminum oxide nanopore arrays, were successfully prepared.

  7. High-flux water desalination with interfacial salt sieving effect in nanoporous carbon composite membranes

    KAUST Repository

    Chen, Wei; Chen, Shuyu; Liang, Tengfei; Zhang, Qiang; Fan, Zhongli; Yin, Hang; Huang, Kuo-Wei; Zhang, Xixiang; Lai, Zhiping; Sheng, Ping

    2018-01-01

    Freshwater flux and energy consumption are two important benchmarks for the membrane desalination process. Here, we show that nanoporous carbon composite membranes, which comprise a layer of porous carbon fibre structures grown on a porous ceramic

  8. Study of preparation and surface morphology of self-ordered nanoporous alumina

    International Nuclear Information System (INIS)

    Rodrigues, Elisa Marchezini; Martins, Maximiliano Delany; Silva, Ronald Arreguy

    2013-01-01

    Nanoporous alumina is a typical material that exhibits self-ordered nanochannels spontaneously organized in hexagonal shape. Produced by anodizing of metallic aluminum, it has been used as a template for production of materials at the nanoscale. This work aimed to study the preparation of nanoporous alumina by anodic anodizing of metallic aluminum substrates. The nanoporous alumina was prepared following the methodology proposed by Masuda and Fukuda (1995), a two-step method consisting of anodizing the aluminum sample in the potentiostatic mode, removing the layer of aluminum oxide (alumina) formed and then repeat the anodization process under the same conditions as the first anodization. This method produces nanoporous alumina with narrow pore diameter distribution and well-ordered structure. (author)

  9. Nanoporous layered silicate AMH-3/cellulose acetate nanocomposite membranes for gas separations

    KAUST Repository

    Kim, Wun-gwi; Lee, Jong Suk; Bucknall, David G.; Koros, William J.; Nair, Sankar

    2013-01-01

    Nanoporous layered silicate/polymer composite membranes are of interest because they can exploit the high aspect ratio of exfoliated selective flakes/layers to enhance molecular sieving and create a highly tortuous transport path for the slower

  10. Nanoporous Activated Carbon Derived from Rice Husk for High Performance Supercapacitor

    Directory of Open Access Journals (Sweden)

    Huaxing Xu

    2014-01-01

    Full Text Available Nanoporous activated carbon material was produced from the waste rice husks (RHs by precarbonizing RHs and activating with KOH. The morphology, structure, and specific surface area were investigated. The nanoporous carbon has the average pore size of 2.2 nm and high specific area of 2523.4 m2 g−1. The specific capacitance of the nanoporous carbon is calculated to be 250 F g−1 at the current density of 1 A g−1 and remains 80% for 198 F g−1 at the current density of 20 A g−1. The nanoporous carbon electrode exhibits long-term cycle life and could keep stable capacitance till 10,000 cycles. The consistently high specific capacitance, rate capacity, and long-term cycle life ability makes it a potential candidate as electrode material for supercapacitor.

  11. Nanoporous carbon tunable resistor/transistor and methods of production thereof

    Science.gov (United States)

    Biener, Juergen; Baumann, Theodore F; Dasgupta, Subho; Hahn, Horst

    2014-04-22

    In one embodiment, a tunable resistor/transistor includes a porous material that is electrically coupled between a source electrode and a drain electrode, wherein the porous material acts as an active channel, an electrolyte solution saturating the active channel, the electrolyte solution being adapted for altering an electrical resistance of the active channel based on an applied electrochemical potential, wherein the active channel comprises nanoporous carbon arranged in a three-dimensional structure. In another embodiment, a method for forming the tunable resistor/transistor includes forming a source electrode, forming a drain electrode, and forming a monolithic nanoporous carbon material that acts as an active channel and selectively couples the source electrode to the drain electrode electrically. In any embodiment, the electrolyte solution saturating the nanoporous carbon active channel is adapted for altering an electrical resistance of the nanoporous carbon active channel based on an applied electrochemical potential.

  12. Self-ordered, controlled structure nanoporous membranes using constant current anodization.

    Science.gov (United States)

    Lee, Kwan; Tang, Yun; Ouyang, Min

    2008-12-01

    We report a constant current (CC) based anodization technique to fabricate and control structure of mechanically stable anodic aluminum oxide (AAO) membranes with a long-range ordered hexagonal nanopore pattern. For the first time we show that interpore distance (Dint) of a self-ordered nanopore feature can be continuously tuned over a broad range with CC anodization and is uniquely defined by the conductivity of sulfuric acid as electrolyte. We further demonstrate that this technique can offer new degrees of freedom for engineering planar nanopore structures by fine tailoring the CC based anodization process. Our results not only facilitate further understanding of self-ordering mechanism of alumina membranes but also provide a fast, simple (without requirement of prepatterning or preoxide layer), and flexible methodology for controlling complex nanoporous structures, thus offering promising practical applications in nanotechnology.

  13. Influence of adsorption thermodynamics on guest diffusivities in nanoporous crystalline materials

    NARCIS (Netherlands)

    Krishna, R.; van Baten, J.M.

    2013-01-01

    Published experimental data, underpinned by molecular simulations, are used to highlight the strong influence of adsorption thermodynamics on diffusivities of guest molecules inside ordered nanoporous crystalline materials such as zeolites, metal-organic frameworks (MOFs), and zeolitic imidazolate

  14. Sodium Dodecyl Sulfate (SDS-Loaded Nanoporous Polymer as Anti-Biofilm Surface Coating Material

    Directory of Open Access Journals (Sweden)

    Sokol Ndoni

    2013-02-01

    Full Text Available Biofilms cause extensive damage to industrial settings. Thus, it is important to improve the existing techniques and develop new strategies to prevent bacterial biofilm formation. In the present study, we have prepared nanoporous polymer films from a self-assembled 1,2-polybutadiene-b-polydimethylsiloxane (1,2-PB-b-PDMS block copolymer via chemical cross-linking of the 1,2-PB block followed by quantitative removal of the PDMS block. Sodium dodecyl sulfate (SDS was loaded into the nanoporous 1,2-PB from aqueous solution. The SDS-loaded nanoporous polymer films were shown to block bacterial attachment in short-term (3 h and significantly reduce biofilm formation in long-term (1 week by gram-negative bacterium Escherichia coli. Tuning the thickness or surface morphology of the nanoporous polymer films allowed to extent the anti-biofilm capability.

  15. Water desalination with a single-layer MoS2 nanopore

    Science.gov (United States)

    Heiranian, Mohammad; Farimani, Amir Barati; Aluru, Narayana R.

    2015-10-01

    Efficient desalination of water continues to be a problem facing the society. Advances in nanotechnology have led to the development of a variety of nanoporous membranes for water purification. Here we show, by performing molecular dynamics simulations, that a nanopore in a single-layer molybdenum disulfide can effectively reject ions and allow transport of water at a high rate. More than 88% of ions are rejected by membranes having pore areas ranging from 20 to 60 Å2. Water flux is found to be two to five orders of magnitude greater than that of other known nanoporous membranes. Pore chemistry is shown to play a significant role in modulating the water flux. Pores with only molybdenum atoms on their edges lead to higher fluxes, which are ~70% greater than that of graphene nanopores. These observations are explained by permeation coefficients, energy barriers, water density and velocity distributions in the pores.

  16. Swelling, Functionalization, and Structural Changes of the Nanoporous Layered Silicates AMH-3 and MCM-22

    KAUST Repository

    Kim, Wun-gwi; Choi, Sunho; Nair, Sankar

    2011-01-01

    Nanoporous layered silicate materials contain 2D-planar sheets of nanoscopic thickness and ordered porous structure. In comparison to porous 3D-framework materials such as zeolites, they have advantages such as significantly increased surface area

  17. Stability and Catalytic Kinetics of Horseradish Peroxidase Confined in Nanoporous SBA-15

    DEFF Research Database (Denmark)

    Ikemoto, Hediki; Chi, Qijin; Ulstrup, Jens

    2010-01-01

    We have synthesized nanoporous silica, SBA-15 in the 1 m size range with the pore diameter of 7.6 nm. The redox enzyme horseradish peroxidase (HRP) was entrapped in the pores to form nanostructured hybrid materials. The catalytic activity of free and immobilized enzyme was first compared at room...... likely due to different hydrogen bonding of water and increased hydration strength of the protein inside the nanopores....

  18. Fabrication and textural characterization of nanoporous carbon electrodes embedded with CuO nanoparticles for supercapacitors

    OpenAIRE

    Kumaresa P S Prasad, Dattatray S Dhawale, Thiripuranthagan Sivakumar, Salem S Aldeyab, Javaid S M Zaidi, Katsuhiko Ariga and Ajayan Vinu

    2011-01-01

    We introduce a novel strategy of fabricating nanoporous carbons loaded with different amounts of CuO nanoparticles via a hard templating approach, using copper-containing mesoporous silica as the template and sucrose as the carbon source. The nature and dispersion of the CuO nanoparticles on the surface of the nanoporous carbons were investigated by x-ray diffraction (XRD), high-resolution scanning electron microscopy (HRSEM) and high-resolution transmission electron microscopy (HRTEM). XRD r...

  19. Fluid-mechanic model for fabrication of nanoporous fibers by electrospinning

    Directory of Open Access Journals (Sweden)

    Fan Chengxu

    2017-01-01

    Full Text Available A charged jet in the electrospinning process for fabrication of nanoporous fibers is studied theoretically. A fluid-mechanic model considering solvent evaporation is established to research the effect of solvent evaporation on nanopore structure formation. The model gives a powerful tool to offering in-depth physical under-standing and controlling over electrospinning parameters such as voltage, flow rate, and solvent evaporation rate.

  20. Fluid-mechanic model for fabrication of nanoporous fibers by electrospinning

    OpenAIRE

    Fan Chengxu; Sun Zhaoyang; Xu Lan

    2017-01-01

    A charged jet in the electrospinning process for fabrication of nanoporous fibers is studied theoretically. A fluid-mechanic model considering solvent evaporation is established to research the effect of solvent evaporation on nanopore structure formation. The model gives a powerful tool to offering in-depth physical under-standing and controlling over electrospinning parameters such as voltage, flow rate, and solvent evaporation rate.

  1. Microstructure evolution in nanoporous gold thin films made from sputter-deposited precursors

    International Nuclear Information System (INIS)

    Gwak, Eun-Ji; Kang, Na-Ri; Baek, Un Bong; Lee, Hae Moo; Nahm, Seung Hoon; Kim, Ju-Young

    2013-01-01

    We fabricate almost crack-free 1.5 μm thick nanoporous gold thin films using free-corrosion dealloying and transfer processes from sputter-deposited precursors. By controlling the temperature and the concentration of the nitric acid solution during free-corrosion dealloying, we obtain ligament sizes in nanoporous gold between 22 and 155 nm. We investigate the effects of dissolution rate of Ag atoms, surface diffusivity of Au atoms and formation of Ag oxide on nanoporosity evolution

  2. Fabrication and characterization of a flow-through nanoporous gold nanowire/AAO composite membrane

    Energy Technology Data Exchange (ETDEWEB)

    Liu, L; Lee, W; Huang, Z; Scholz, R; Goesele, U [Max Planck Institute of Microstructure Physics, Weinberg 2, D-06120 Halle (Germany)

    2008-08-20

    The fabrication of a composite membrane of nanoporous gold nanowires and anodic aluminum oxide (AAO) is demonstrated by the electrodeposition of Au-Ag alloy nanowires into an AAO membrane, followed by selective etching of silver from the alloy nanowires. This composite membrane is advantageous for flow-through type catalytic reactions. The morphology evolution of the nanoporous gold nanowires as a function of the diameter of the Au-Ag nanowire 'precursors' is also investigated.

  3. Fabrication and characterization of a flow-through nanoporous gold nanowire/AAO composite membrane

    International Nuclear Information System (INIS)

    Liu, L; Lee, W; Huang, Z; Scholz, R; Goesele, U

    2008-01-01

    The fabrication of a composite membrane of nanoporous gold nanowires and anodic aluminum oxide (AAO) is demonstrated by the electrodeposition of Au-Ag alloy nanowires into an AAO membrane, followed by selective etching of silver from the alloy nanowires. This composite membrane is advantageous for flow-through type catalytic reactions. The morphology evolution of the nanoporous gold nanowires as a function of the diameter of the Au-Ag nanowire 'precursors' is also investigated

  4. Fabrication and characterization of a flow-through nanoporous gold nanowire/AAO composite membrane.

    Science.gov (United States)

    Liu, L; Lee, W; Huang, Z; Scholz, R; Gösele, U

    2008-08-20

    The fabrication of a composite membrane of nanoporous gold nanowires and anodic aluminum oxide (AAO) is demonstrated by the electrodeposition of Au-Ag alloy nanowires into an AAO membrane, followed by selective etching of silver from the alloy nanowires. This composite membrane is advantageous for flow-through type catalytic reactions. The morphology evolution of the nanoporous gold nanowires as a function of the diameter of the Au-Ag nanowire 'precursors' is also investigated.

  5. Chiral silicon nanostructures

    International Nuclear Information System (INIS)

    Schubert, E.; Fahlteich, J.; Hoeche, Th.; Wagner, G.; Rauschenbach, B.

    2006-01-01

    Glancing angle ion beam assisted deposition is used for the growth of amorphous silicon nanospirals onto [0 0 1] silicon substrates in a temperature range from room temperature to 475 deg. C. The nanostructures are post-growth annealed in an argon atmosphere at various temperatures ranging from 400 deg. C to 800 deg. C. Recrystallization of silicon within the persisting nanospiral configuration is demonstrated for annealing temperatures above 800 deg. C. Transmission electron microscopy and Raman spectroscopy are used to characterize the silicon samples prior and after temperature treatment

  6. Silicon web process development

    Science.gov (United States)

    Duncan, C. S.; Seidensticker, R. G.; Mchugh, J. P.; Skutch, M. E.; Driggers, J. M.; Hopkins, R. H.

    1981-01-01

    The silicon web process takes advantage of natural crystallographic stabilizing forces to grow long, thin single crystal ribbons directly from liquid silicon. The ribbon, or web, is formed by the solidification of a liquid film supported by surface tension between two silicon filaments, called dendrites, which border the edges of the growing strip. The ribbon can be propagated indefinitely by replenishing the liquid silicon as it is transformed to crystal. The dendritic web process has several advantages for achieving low cost, high efficiency solar cells. These advantages are discussed.

  7. Understanding improved osteoblast behavior on select nanoporous anodic alumina

    Directory of Open Access Journals (Sweden)

    Ni S

    2014-07-01

    Full Text Available Siyu Ni,1 Changyan Li,1 Shirong Ni,2 Ting Chen,1 Thomas J Webster3,4 1College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai, People’s Republic of China; 2Department of Pathophysiology, Wenzhou Medical University, Wenzhou, People’s Republic of China; 3Department of Chemical Engineering, College of Engineering, Northeastern University, Boston, MA, USA; 4Center of Excellence for Advanced Materials Research, King Abdulaziz University, Jeddah, Saudi Arabia Abstract: The aim of this study was to prepare different sized porous anodic alumina (PAA and examine preosteoblast (MC3T3-E1 attachment and proliferation on such nanoporous surfaces. In this study, PAA with tunable pore sizes (25 nm, 50 nm, and 75 nm were fabricated by a two-step anodizing procedure in oxalic acid. The surface morphology and elemental composition of PAA were characterized by field emission scanning electron microscopy and X-ray photoelectron spectroscopy analysis. The nanopore arrays on all of the PAA samples were highly regular. X-ray photoelectron spectroscopy analysis suggested that the chemistry of PAA and flat aluminum surfaces were similar. However, contact angles were significantly greater on all of the PAA compared to flat aluminum substrates, which consequently altered protein adsorption profiles. The attachment and proliferation of preosteoblasts were determined for up to 7 days in culture using field emission scanning electron microscopy and a Cell Counting Kit-8. Results showed that nanoporous surfaces did not enhance initial preosteoblast attachment, whereas preosteoblast proliferation dramatically increased when the PAA pore size was either 50 nm or 75 nm compared to all other samples (P<0.05. Thus, this study showed that one can alter surface energy of aluminum by modifying surface nano-roughness alone (and not changing chemistry through an anodization process to improve osteoblast density, and, thus, should be

  8. Recent progress in molecular simulation of nanoporous graphene membranes for gas separation

    Science.gov (United States)

    Fatemi, S. Mahmood; Baniasadi, Aminreza; Moradi, Mahrokh

    2017-07-01

    If an ideal membrane for gas separation is to be obtained, the following three characteristics should be considered: the membrane should be as thin as possible, be mechanically robust, and have welldefined pore sizes. These features will maximize its solvent flux, preserve it from fracture, and guarantee its selectivity. Graphene is made up of a hexagonal honeycomb lattice of carbon atoms with sp 2 hybridization state forming a one-atom-thick sheet of graphite. Following conversion of the honeycomb lattices into nanopores with a specific geometry and size, a nanoporous graphene membrane that offers high efficiency as a separation membrane because of the ultrafast molecular permeation rate as a result of its one-atom thickness is obtained. Applications of nanoporous graphene membranes for gas separation have been receiving remarkably increasing attention because nanoporous graphene membranes show promising results in this area. This review focuses on the recent advances in nanoporous graphene membranes for applications in gas separation, with a major emphasis on theoretical works. The attractive properties of nanoporous graphene membranes introduce make them appropriate candidates for gas separation and gas molecular-sieving processes in nanoscale dimensions.

  9. Nanoporous biomaterials for uremic toxin adsorption in artificial kidney systems: A review.

    Science.gov (United States)

    Cheah, Wee-Keat; Ishikawa, Kunio; Othman, Radzali; Yeoh, Fei-Yee

    2017-07-01

    Hemodialysis, one of the earliest artificial kidney systems, removes uremic toxins via diffusion through a semipermeable porous membrane into the dialysate fluid. Miniaturization of the present hemodialysis system into a portable and wearable device to maintain continuous removal of uremic toxins would require that the amount of dialysate used within a closed-system is greatly reduced. Diffused uremic toxins within a closed-system dialysate need to be removed to maintain the optimum concentration gradient for continuous uremic toxin removal by the dialyzer. In this dialysate regenerative system, adsorption of uremic toxins by nanoporous biomaterials is essential. Throughout the years of artificial kidney development, activated carbon has been identified as a potential adsorbent for uremic toxins. Adsorption of uremic toxins necessitates nanoporous biomaterials, especially activated carbon. Nanoporous biomaterials are also utilized in hemoperfusion for uremic toxin removal. Further miniaturization of artificial kidney system and improvements on uremic toxin adsorption capacity would require high performance nanoporous biomaterials which possess not only higher surface area, controlled pore size, but also designed architecture or structure and surface functional groups. This article reviews on various nanoporous biomaterials used in current artificial kidney systems and several emerging nanoporous biomaterials. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 1232-1240, 2017. © 2016 Wiley Periodicals, Inc.

  10. Hierarchical nanoporous metals as a path toward the ultimate three-dimensional functionality.

    Science.gov (United States)

    Fujita, Takeshi

    2017-01-01

    Nanoporous metals prepared via dealloying or selective leaching of solid solution alloys and compounds represent an emerging class of materials. They possess a three-dimensional (3D) structure of randomly interpenetrating ligaments/nanopores with sizes between 5 nm and several tens of micrometers, which can be tuned by varying their preparation conditions (such as dealloying time and temperature) or additional thermal coarsening. As compared to other nanostructured materials, nanoporous metals have many advantages, including their bicontinuous structure, tunable pore sizes, bulk form, good electrical conductivity, and high structural stability. Therefore, nanoporous metals represent ideal 3D materials with versatile functionality, which can be utilized in various fields. In this review, we describe the recent applications of nanoporous metals in molecular detection, catalysis, 3D graphene synthesis, hierarchical pore formation, and additive manufacturing (3D printing) together with our own achievements in these areas. Finally, we discuss possible ways of realizing the ultimate 3D functionality beyond the scope of nanoporous metals.

  11. Pore structure and function of synthetic nanopores with fixed charges: tip shape and rectification properties

    Energy Technology Data Exchange (ETDEWEB)

    RamIrez, Patricio [Departament de Fisica Aplicada, Universitat Politecnica de Valencia, E-46022 Valencia (Spain); Apel, Pavel Yu [Flerov Laboratory of Nuclear Reactions, Joint Institute for Nuclear Research, Joliot-Curie street 6, 141980 Dubna (Russian Federation); Cervera, Javier; Mafe, Salvador [Departament de Fisica de la Terra i Termodinamica, Universitat de Valencia, E-46100 Burjassot (Spain)], E-mail: patraho@fis.upv.es

    2008-08-06

    We present a complete theoretical study of the relationship between the structure (tip shape and dimensions) and function (selectivity and rectification) of asymmetric nanopores on the basis of previous experimental studies. The theoretical model uses a continuum approach based on the Nernst-Planck equations. According to our results, the nanopore transport properties, such as current-voltage (I-V) characteristics, conductance, rectification ratio, and selectivity, are dictated mainly by the shape of the pore tip (we have distinguished bullet-like, conical, trumpet-like, and hybrid shapes) and the concentration of pore surface charges. As a consequence, the nanopore performance in practical applications will depend not only on the base and tip openings but also on the pore shape. In particular, we show that the pore opening dimensions estimated from the pore conductance can be very different, depending on the pore shape assumed. The results obtained can also be of practical relevance for the design of nanopores, nanopipettes, and nanoelectrodes, where the electrical interactions between the charges attached to the nanostructure and the mobile charges confined in the reduced volume of the inside solution dictate the device performance in practical applications. Because single tracks are the elementary building blocks for nanoporous membranes, the understanding and control of their individual properties should also be crucial in protein separation, water desalination, and bio-molecule detection using arrays of identical nanopores.

  12. Pore structure and function of synthetic nanopores with fixed charges: tip shape and rectification properties

    International Nuclear Information System (INIS)

    RamIrez, Patricio; Apel, Pavel Yu; Cervera, Javier; Mafe, Salvador

    2008-01-01

    We present a complete theoretical study of the relationship between the structure (tip shape and dimensions) and function (selectivity and rectification) of asymmetric nanopores on the basis of previous experimental studies. The theoretical model uses a continuum approach based on the Nernst-Planck equations. According to our results, the nanopore transport properties, such as current-voltage (I-V) characteristics, conductance, rectification ratio, and selectivity, are dictated mainly by the shape of the pore tip (we have distinguished bullet-like, conical, trumpet-like, and hybrid shapes) and the concentration of pore surface charges. As a consequence, the nanopore performance in practical applications will depend not only on the base and tip openings but also on the pore shape. In particular, we show that the pore opening dimensions estimated from the pore conductance can be very different, depending on the pore shape assumed. The results obtained can also be of practical relevance for the design of nanopores, nanopipettes, and nanoelectrodes, where the electrical interactions between the charges attached to the nanostructure and the mobile charges confined in the reduced volume of the inside solution dictate the device performance in practical applications. Because single tracks are the elementary building blocks for nanoporous membranes, the understanding and control of their individual properties should also be crucial in protein separation, water desalination, and bio-molecule detection using arrays of identical nanopores

  13. Pore structure and function of synthetic nanopores with fixed charges: tip shape and rectification properties.

    Science.gov (United States)

    Ramírez, Patricio; Apel, Pavel Yu; Cervera, Javier; Mafé, Salvador

    2008-08-06

    We present a complete theoretical study of the relationship between the structure (tip shape and dimensions) and function (selectivity and rectification) of asymmetric nanopores on the basis of previous experimental studies. The theoretical model uses a continuum approach based on the Nernst-Planck equations. According to our results, the nanopore transport properties, such as current-voltage (I-V) characteristics, conductance, rectification ratio, and selectivity, are dictated mainly by the shape of the pore tip (we have distinguished bullet-like, conical, trumpet-like, and hybrid shapes) and the concentration of pore surface charges. As a consequence, the nanopore performance in practical applications will depend not only on the base and tip openings but also on the pore shape. In particular, we show that the pore opening dimensions estimated from the pore conductance can be very different, depending on the pore shape assumed. The results obtained can also be of practical relevance for the design of nanopores, nanopipettes, and nanoelectrodes, where the electrical interactions between the charges attached to the nanostructure and the mobile charges confined in the reduced volume of the inside solution dictate the device performance in practical applications. Because single tracks are the elementary building blocks for nanoporous membranes, the understanding and control of their individual properties should also be crucial in protein separation, water desalination, and bio-molecule detection using arrays of identical nanopores.

  14. Computational and experimental study of nanoporous membranes for water desalination and decontamination.

    Energy Technology Data Exchange (ETDEWEB)

    Hickner, Michael A. (Penn State University, University Park, PA); Chinn, Douglas Alan (Sandia National Laboratories, Albuquerque, NM); Adalsteinsson, Helgi; Long, Kevin R. (Texas Tech University, Lubbock, TX); Kent, Michael Stuart (Sandia National Laboratories, Albuquerque, NM); Debusschere, Bert J.; Zendejas, Frank J.; Tran, Huu M.; Najm, Habib N.; Simmons, Blake Alexander

    2008-11-01

    Fundamentals of ion transport in nanopores were studied through a joint experimental and computational effort. The study evaluated both nanoporous polymer membranes and track-etched nanoporous polycarbonate membranes. The track-etched membranes provide a geometrically well characterized platform, while the polymer membranes are more closely related to ion exchange systems currently deployed in RO and ED applications. The experimental effort explored transport properties of the different membrane materials. Poly(aniline) membranes showed that flux could be controlled by templating with molecules of defined size. Track-etched polycarbonate membranes were modified using oxygen plasma treatments, UV-ozone exposure, and UV-ozone with thermal grafting, providing an avenue to functionalized membranes, increased wettability, and improved surface characteristic lifetimes. The modeling effort resulted in a novel multiphysics multiscale simulation model for field-driven transport in nanopores. This model was applied to a parametric study of the effects of pore charge and field strength on ion transport and charge exclusion in a nanopore representative of a track-etched polycarbonate membrane. The goal of this research was to uncover the factors that control the flux of ions through a nanoporous material and to develop tools and capabilities for further studies. Continuation studies will build toward more specific applications, such as polymers with attached sulfonate groups, and complex modeling methods and geometries.

  15. Precision Photothermal Annealing of Nanoporous Gold Thin Films for the Microfabrication of a Single-chip Material Libraries

    Energy Technology Data Exchange (ETDEWEB)

    Harris, C. D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Shen, N. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Rubenchik, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Demos, S. G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Matthews, M. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-06-30

    Single-chip material libraries of thin films of nanostructured materials are a promising approach for high throughput studies of structure-property relationship in the fields of physics and biology. Nanoporous gold (np-Au), produced by an alloy corrosion process, is a nanostructured material of specific interest in both these fields. One attractive property of np-Au is its self-similar coarsening behavior by thermally induced surface diffusion. However, traditional heat application techniques for the modification of np-Au are bulk processes that cannot be used to generate a library of different pore sizes on a single chip. Laser micromachining offers an attractive solution to this problem by providing a means to apply energy with high spatial and temporal resolution. In the present study we use finite element multiphysics simulations to predict the effects of laser mode (continuous-wave vs. pulsed) and supporting substrate thermal conductivity on the local np-Au film temperatures during photothermal annealing and subsequently investigate the mechanisms by which the np-Au network is coarsening. Our simulations predict that continuous-wave mode laser irradiation on a silicon supporting substrate supports the widest range of morphologies that can be created through the photothermal annealing of thin film np-Au. Using this result we successfully fabricate a single-chip material library consisting of 81 np-Au samples of 9 different morphologies for use in increased throughput material interaction studies.

  16. Incorporation of sol-gel SnO{sub 2}:Sb into nanoporous SiO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Canut, B. [Laboratoire de Physique de la Matiere Condensee et Nanostructures, Universite ClaudeBernard Lyon I, UMR CNRS 5586, Dept. de Physique des Materiaux, 43 Boulevard du 11 Novembre 1918, 69622 Villeurbanne Cedex (France)]. E-mail: bruno.canut@lpmcn.univ-lyon1.fr; Blanchin, M.G. [Laboratoire de Physique de la Matiere Condensee et Nanostructures, Universite ClaudeBernard Lyon I, UMR CNRS 5586, Dept. de Physique des Materiaux, 43 Boulevard du 11 Novembre 1918, 69622 Villeurbanne Cedex (France); Ramos-Canut, S. [Laboratoire de Physique de la Matiere Condensee et Nanostructures, Universite ClaudeBernard Lyon I, UMR CNRS 5586, Dept. de Physique des Materiaux, 43 Boulevard du 11 Novembre 1918, 69622 Villeurbanne Cedex (France); Teodorescu, V. [National Institute for Physics of Materials, Magurele, R-76900 Bucharest (Romania); Toulemonde, M. [Centre Interdisciplinaire de Recherche Ions Laser, CIRIL-GANIL, rue Claude Bloch, BP 5133, 14070 Caen Cedex 5 (France)

    2006-04-15

    Silicon oxide films thermally grown on Si(1 0 0) wafers were irradiated with 200 MeV {sup 197}Au ions in the 10{sup 9}-10{sup 1} cm{sup -2} fluence range. The targets were then etched at room temperature in aqueous HF solution (1 vol.%) for various durations. Atomic force microscopy (AFM) in the tapping mode was used to probe the processed surfaces. Conical holes with a low size dispersion were evidenced. Their surface diameter varies between 20 and 70 nm, depending on the etching time. Sol-gel dip coating technique, associated with a further annealing treatment performed at 500 {sup o}C for 15 min, was used to fill the nanopores created in SiO{sub 2} with a transparent conductive oxide (SnO{sub 2} doped with antimony). Transmission electron microscopy (TEM) performed on cross-sectional specimen showed that SnO{sub 2}:Sb crystallites of {approx}5 nm mean size are trapped in the holes without degrading their geometry.

  17. Synthesis of high-quality mesoporous silicon particles for enhanced lithium storage performance

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Chundong, E-mail: apcdwang@hust.edu.cn [School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074 (China); Center of Super-Diamond and Advanced Films (COSDAF), Department of Physics and Materials Science, City University of Hong Kong, Kowloon, Hong Kong SAR (China); Ren, Jianguo [Center of Super-Diamond and Advanced Films (COSDAF), Department of Physics and Materials Science, City University of Hong Kong, Kowloon, Hong Kong SAR (China); Chen, Hao [Department of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou (China); Zhang, Yi [School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Wuhan, 430073 (China); Ostrikov, Kostya [School of Chemistry, Physics, and Mechanical Engineering, Queensland University of Technology, Brisbane 4000, QLD (Australia); Manufacturing Flagship, CSIRO, P. O. Box 218, Lindfield, NSW 2070 (Australia); Zhang, Wenjun [Center of Super-Diamond and Advanced Films (COSDAF), Department of Physics and Materials Science, City University of Hong Kong, Kowloon, Hong Kong SAR (China); Li, Yi, E-mail: liyi@suda.edu.cn [Department of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou (China); Center of Super-Diamond and Advanced Films (COSDAF), Department of Physics and Materials Science, City University of Hong Kong, Kowloon, Hong Kong SAR (China)

    2016-04-15

    Silicon has been considered as one of the most promising anode materials for high-capacity lithium-ion batteries (LIBs) due to its ultrahigh theoretical capacity, abundance, and environmentally benign nature. Nonetheless, the severe break during the prolonged cycling results in poor electrochemical performance, which hinders its practical application. Herein, we report the synthesis of novel mesoporous silicon particles with a facile template method by using a magnesiothermic reduction for LIBs. The obtained silicon nanoparticles are highly porous with densely porous cavities (20–40 nm) on the wall, of which it presents good crystallization. Electrochemical measurements showed that the mesoporous silicon nanoparticles delivered a high reversible specific capacity of 910 mA h g{sup −1} at a high current density of 1200 mA g{sup −1} over 50 cycles. The specific capacity at such high current density is still over twofold than that of commercial graphite anode, suggesting that the nanoporous Si architectures is suitable for high-performance Si-based anodes for lithium ion batteries in terms of capacity, cycle life, and rate capacity. - Highlights: • Silica nanotubes were prepared with a facile template method. • Novel mesoporous silicon particles were obtained by magnesiothermic reduction. • High-Performance LIBs were achieved by using mesoporous Si particle Electrodes.

  18. Bistable collective behavior of polymers tethered in a nanopore

    Science.gov (United States)

    Osmanovic, Dino; Bailey, Joe; Harker, Anthony H.; Fassati, Ariberto; Hoogenboom, Bart W.; Ford, Ian J.

    2012-06-01

    Polymer-coated pores play a crucial role in nucleo-cytoplasmic transport and in a number of biomimetic and nanotechnological applications. Here we present Monte Carlo and Density Functional Theory approaches to identify different collective phases of end-grafted polymers in a nanopore and to study their relative stability as a function of intermolecular interactions. Over a range of system parameters that is relevant for nuclear pore complexes, we observe two distinct phases: one with the bulk of the polymers condensed at the wall of the pore, and the other with the polymers condensed along its central axis. The relative stability of these two phases depends on the interpolymer interactions. The existence the two phases suggests a mechanism in which marginal changes in these interactions, possibly induced by nuclear transport receptors, cause the pore to transform between open and closed configurations, which will influence transport through the pore.

  19. Effects of rotational symmetry breaking in polymer-coated nanopores

    Science.gov (United States)

    Osmanović, D.; Kerr-Winter, M.; Eccleston, R. C.; Hoogenboom, B. W.; Ford, I. J.

    2015-01-01

    The statistical theory of polymers tethered around the inner surface of a cylindrical channel has traditionally employed the assumption that the equilibrium density of the polymers is independent of the azimuthal coordinate. However, simulations have shown that this rotational symmetry can be broken when there are attractive interactions between the polymers. We investigate the phases that emerge in these circumstances, and we quantify the effect of the symmetry assumption on the phase behavior of the system. In the absence of this assumption, one can observe large differences in the equilibrium densities between the rotationally symmetric case and the non-rotationally symmetric case. A simple analytical model is developed that illustrates the driving thermodynamic forces responsible for this symmetry breaking. Our results have implications for the current understanding of the behavior of polymers in cylindrical nanopores.

  20. Effects of rotational symmetry breaking in polymer-coated nanopores

    Energy Technology Data Exchange (ETDEWEB)

    Osmanović, D.; Hoogenboom, B. W.; Ford, I. J. [London Centre for Nanotechnology (LCN) and Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom); Kerr-Winter, M.; Eccleston, R. C. [Centre for Mathematics, Physics and Engineering in the Life Sciences and Experimental Biology, University College London, Gower Street, London WC1E 6BT (United Kingdom)

    2015-01-21

    The statistical theory of polymers tethered around the inner surface of a cylindrical channel has traditionally employed the assumption that the equilibrium density of the polymers is independent of the azimuthal coordinate. However, simulations have shown that this rotational symmetry can be broken when there are attractive interactions between the polymers. We investigate the phases that emerge in these circumstances, and we quantify the effect of the symmetry assumption on the phase behavior of the system. In the absence of this assumption, one can observe large differences in the equilibrium densities between the rotationally symmetric case and the non-rotationally symmetric case. A simple analytical model is developed that illustrates the driving thermodynamic forces responsible for this symmetry breaking. Our results have implications for the current understanding of the behavior of polymers in cylindrical nanopores.

  1. Real-time visualization of perforin nanopore assembly

    Science.gov (United States)

    Leung, Carl; Hodel, Adrian W.; Brennan, Amelia J.; Lukoyanova, Natalya; Tran, Sharon; House, Colin M.; Kondos, Stephanie C.; Whisstock, James C.; Dunstone, Michelle A.; Trapani, Joseph A.; Voskoboinik, Ilia; Saibil, Helen R.; Hoogenboom, Bart W.

    2017-05-01

    Perforin is a key protein of the vertebrate immune system. Secreted by cytotoxic lymphocytes as soluble monomers, perforin can self-assemble into oligomeric pores of 10-20 nm inner diameter in the membranes of virus-infected and cancerous cells. These large pores facilitate the entry of pro-apoptotic granzymes, thereby rapidly killing the target cell. To elucidate the pathways of perforin pore assembly, we carried out real-time atomic force microscopy and electron microscopy studies. Our experiments reveal that the pore assembly proceeds via a membrane-bound prepore intermediate state, typically consisting of up to approximately eight loosely but irreversibly assembled monomeric subunits. These short oligomers convert to more closely packed membrane nanopore assemblies, which can subsequently recruit additional prepore oligomers to grow the pore size.

  2. Hexadecane trapped in nano-pores of silica-aerogel

    International Nuclear Information System (INIS)

    Slavikova, B.; Jesenak, K.; Iskrova, M.; Majernik, V.; Sausa, O.; Kristiak, J.

    2009-01-01

    Ways of filling of the high-porous silica-aerogel with hydrocarbon C 16 H 34 and its efficient removal from the pores by physical method of the Positron Annihilation Spectroscopy were studied. As the most effective way to fill the SiO 2 aerogel appears through the implementation of a liquid phase, while the most appropriate way of removing of hexadecane is firing at an elevated temperature. Molecular system of hexadecane closed in nano-pores of silica-aerogel behaves otherwise than volume system of the same molecules. In the case of pure hexadecane phase transition was observed at 291 K, while solidification process is gradual with decrease of temperature in cetane trapped in pores of silica-aerogel. The results of the periods of life of o-Ps indicate greater turbidity in the pores of the molecular system compared to the volume sample of hexadecane.

  3. Charging dynamics of supercapacitors with narrow cylindrical nanopores

    Science.gov (United States)

    Lee, Alpha A.; Kondrat, Svyatoslav; Oshanin, Gleb; Kornyshev, Alexei A.

    2014-08-01

    We present a coarse-grained, continuum kinetic theory for charging supercapacitors with narrow cylindrical nanopores. The theory reveals that the occupancy of a nonpolarized pore and the energy barrier for ion-ion interdiffusion are the key issues controlling the different regimes of dynamic response. For ‘ionophobic’ pores, where the pore is empty at no applied voltage, charge density advances into the pore via diffusion-like dynamics. The mechanism of charging an ‘ionophilic’ pore is starkly different: for moderate ionophilicities, co-ions are expelled from the pore in a front-like manner, with significant ‘congestion’ at the pore entrance predicted for strong ionophilicity. We thus show that pore ionophilicity is detrimental to the speed of charging/discharging cycles, whereas making pores more ionophobic can substantially accelerate charging and cyclic recharging.

  4. Nanopore Current Oscillations: Nonlinear Dynamics on the Nanoscale.

    Science.gov (United States)

    Hyland, Brittany; Siwy, Zuzanna S; Martens, Craig C

    2015-05-21

    In this Letter, we describe theoretical modeling of an experimentally realized nanoscale system that exhibits the general universal behavior of a nonlinear dynamical system. In particular, we consider the description of voltage-induced current fluctuations through a single nanopore from the perspective of nonlinear dynamics. We briefly review the experimental system and its behavior observed and then present a simple phenomenological nonlinear model that reproduces the qualitative behavior of the experimental data. The model consists of a two-dimensional deterministic nonlinear bistable oscillator experiencing both dissipation and random noise. The multidimensionality of the model and the interplay between deterministic and stochastic forces are both required to obtain a qualitatively accurate description of the physical system.

  5. Finite element analysis of mechanical stability of coarsened nanoporous gold

    International Nuclear Information System (INIS)

    Cho, Hoon-Hwe; Chen-Wiegart, Yu-chen Karen; Dunand, David C.

    2016-01-01

    The mechanical stability of nanoporous gold (np-Au) at various stages of thermal coarsening is studied via finite element analysis under volumetric compression using np-Au architectures imaged via X-ray nano-tomography. As the np-Au is coarsened thermally over ligament sizes ranging from 185 to 465 nm, the pore volume fraction is determinant for the mechanical stability of the coarsened np-Au, unlike the curvature and surface orientation of the ligaments. The computed Young's modulus and yield strength of the structures are compared with the Gibson–Ashby model. The geometry of the structures determines the locations where stress concentrations occur at the onset of yielding.

  6. Using nanopore sequencing to get complete genomes from complex samples

    DEFF Research Database (Denmark)

    Kirkegaard, Rasmus Hansen; Karst, Søren Michael; Nielsen, Per Halkjær

    The advantages of “next generation sequencing” has come at the cost of genome finishing. The dominant sequencing technology provides short reads of 150-300 bp, which has made genome assembly very difficult as the reads do not span important repeat regions. Genomes have thus been added...... to the databases as fragmented assemblies and not as finished contigs that resemble the chromosomes in which the DNA is organised within the cells. This is especially troublesome for genomes derived from complex metagenome sequencing. Databases with incomplete genomes can lead to false conclusions about...... the absence of genes and functional predictions of the organisms. Furthermore, it is common that repetitive elements and marker genes such as the 16S rRNA gene are missing completely from these genome bins. Using nanopore long reads, we demonstrate that it is possible to span these regions and make complete...

  7. Getting complete genomes from complex samples using nanopore sequencing

    DEFF Research Database (Denmark)

    Kirkegaard, Rasmus Hansen; Karst, Søren Michael; Albertsen, Mads

    Short read sequencing and metagenomic binning workflows have made it possible to extract bacterial genome bins from environmental microbial samples containing hundreds to thousands of different species. However, these genome bins often do not represent complete genomes, as they are mostly...... fragmented, incomplete and often contaminated with foreign DNA and with no robust strategies to validate the quality. The value of these `draft genomes` have limited, lasting value to the scientific community, as gene synteny is broken and the uncertainty of what is missing. The genetic material most often...... missed is important multi-copy and/or conserved marker genes such as the 16S rRNA gene, as sequence micro-heterogeneity prevents assembly of these genes in the de novo assembly. We demonstrate that using nanopore long reads it is now possible to overcome these issues and make complete genomes from...

  8. Radiative human body cooling by nanoporous polyethylene textile.

    Science.gov (United States)

    Hsu, Po-Chun; Song, Alex Y; Catrysse, Peter B; Liu, Chong; Peng, Yucan; Xie, Jin; Fan, Shanhui; Cui, Yi

    2016-09-02

    Thermal management through personal heating and cooling is a strategy by which to expand indoor temperature setpoint range for large energy saving. We show that nanoporous polyethylene (nanoPE) is transparent to mid-infrared human body radiation but opaque to visible light because of the pore size distribution (50 to 1000 nanometers). We processed the material to develop a textile that promotes effective radiative cooling while still having sufficient air permeability, water-wicking rate, and mechanical strength for wearability. We developed a device to simulate skin temperature that shows temperatures 2.7° and 2.0°C lower when covered with nanoPE cloth and with processed nanoPE cloth, respectively, than when covered with cotton. Our processed nanoPE is an effective and scalable textile for personal thermal management. Copyright © 2016, American Association for the Advancement of Science.

  9. Phase diagram of supercooled water confined to hydrophilic nanopores

    Science.gov (United States)

    Limmer, David T.; Chandler, David

    2012-07-01

    We present a phase diagram for water confined to cylindrical silica nanopores in terms of pressure, temperature, and pore radius. The confining cylindrical wall is hydrophilic and disordered, which has a destabilizing effect on ordered water structure. The phase diagram for this class of systems is derived from general arguments, with parameters taken from experimental observations and computer simulations and with assumptions tested by computer simulation. Phase space divides into three regions: a single liquid, a crystal-like solid, and glass. For large pores, radii exceeding 1 nm, water exhibits liquid and crystal-like behaviors, with abrupt crossovers between these regimes. For small pore radii, crystal-like behavior is unstable and water remains amorphous for all non-zero temperatures. At low enough temperatures, these states are glasses. Several experimental results for supercooled water can be understood in terms of the phase diagram we present.

  10. Carbon dioxide sorption in a nanoporous octahedral molecular sieve

    Science.gov (United States)

    Williamson, Izaak; Nelson, Eric B.; Li, Lan

    2015-08-01

    We have performed first-principles density functional theory calculations, incorporated with van der Waals interactions, to study CO2 adsorption and diffusion in nanoporous solid—OMS-2 (Octahedral Molecular Sieve). We found the charge, type, and mobility of a cation, accommodated in a porous OMS-2 material for structural stability, can affect not only the OMS-2 structural features but also CO2 sorption performance. This paper targets K+, Na+, and Ba2+ cations. First-principles energetics and electronic structure calculations indicate that Ba2+ has the strongest interaction with the OMS-2 porous surface due to valence electrons donation to the OMS-2 and molecular orbital hybridization. However, the Ba-doped OMS-2 has the worst CO2 uptake capacity. We also found evidence of sorption hysteresis in the K- and Na-doped OMS-2 materials.

  11. Ordered nanoporous carbon for increasing CO2 capture

    International Nuclear Information System (INIS)

    Yoo, Hye-Min; Lee, Seul-Yi; Park, Soo-Jin

    2013-01-01

    Ordered nanoporous carbons (ONCs) were prepared using a soft-templating method. The prepared ONCs materials were subjected to a controlled carbonization temperature over the temperature range, 700–1000 °C, to increase the specific surface area and total pore volume of ordered nanoporous carbon followed by carbonization of the phenolic resin. ONCs materials synthesized at various carbonization temperatures were used as adsorbents to improve the CO 2 adsorption efficiency. The surface properties of the ONCs materials were examined by X-ray photoelectron spectroscopy. The structural properties of the ONCs materials were analyzed by X-ray diffraction. The textural properties of the ONCs materials were examined using the N 2 /77 K adsorption isotherms according to the Brunauer–Emmett–Teller equation. The CO 2 adsorption capacity was measured by CO 2 isothermal adsorption at 298 K/30 bar and 298 K/1 bar. The carbonization temperature was found to have a major effect on the CO 2 adsorption capacity, resulting from the specific surface area and total pore volumes of the ONCs materials. - Graphical abstract: This schematic diagram described synthesis of ONCs. Highlights: ► ONCs materials can be prepared readily using the direct-triblock-copolymer-templating method. ► The distributions show that prominent development can be observed around the micro-pore region. ► The soft-templating method provides opportunities for controlling the pore structure of ONCs. ► From thermal power plants for CO2 capture by adsorption technology, is a new direction.

  12. Periodically poled silicon

    Science.gov (United States)

    Hon, Nick K.; Tsia, Kevin K.; Solli, Daniel R.; Khurgin, Jacob B.; Jalali, Bahram

    2010-02-01

    Bulk centrosymmetric silicon lacks second-order optical nonlinearity χ(2) - a foundational component of nonlinear optics. Here, we propose a new class of photonic device which enables χ(2) as well as quasi-phase matching based on periodic stress fields in silicon - periodically-poled silicon (PePSi). This concept adds the periodic poling capability to silicon photonics, and allows the excellent crystal quality and advanced manufacturing capabilities of silicon to be harnessed for devices based on χ(2)) effects. The concept can also be simply achieved by having periodic arrangement of stressed thin films along a silicon waveguide. As an example of the utility, we present simulations showing that mid-wave infrared radiation can be efficiently generated through difference frequency generation from near-infrared with a conversion efficiency of 50% based on χ(2) values measurements for strained silicon reported in the literature [Jacobson et al. Nature 441, 199 (2006)]. The use of PePSi for frequency conversion can also be extended to terahertz generation. With integrated piezoelectric material, dynamically control of χ(2)nonlinearity in PePSi waveguide may also be achieved. The successful realization of PePSi based devices depends on the strength of the stress induced χ(2) in silicon. Presently, there exists a significant discrepancy in the literature between the theoretical and experimentally measured values. We present a simple theoretical model that produces result consistent with prior theoretical works and use this model to identify possible reasons for this discrepancy.

  13. Nonlinear silicon photonics

    Science.gov (United States)

    Tsia, Kevin K.; Jalali, Bahram

    2010-05-01

    An intriguing optical property of silicon is that it exhibits a large third-order optical nonlinearity, with orders-ofmagnitude larger than that of silica glass in the telecommunication band. This allows efficient nonlinear optical interaction at relatively low power levels in a small footprint. Indeed, we have witnessed a stunning progress in harnessing the Raman and Kerr effects in silicon as the mechanisms for enabling chip-scale optical amplification, lasing, and wavelength conversion - functions that until recently were perceived to be beyond the reach of silicon. With all the continuous efforts developing novel techniques, nonlinear silicon photonics is expected to be able to reach even beyond the prior achievements. Instead of providing a comprehensive overview of this field, this manuscript highlights a number of new branches of nonlinear silicon photonics, which have not been fully recognized in the past. In particular, they are two-photon photovoltaic effect, mid-wave infrared (MWIR) silicon photonics, broadband Raman effects, inverse Raman scattering, and periodically-poled silicon (PePSi). These novel effects and techniques could create a new paradigm for silicon photonics and extend its utility beyond the traditionally anticipated applications.

  14. Nonlinear silicon photonics

    Science.gov (United States)

    Borghi, M.; Castellan, C.; Signorini, S.; Trenti, A.; Pavesi, L.

    2017-09-01

    Silicon photonics is a technology based on fabricating integrated optical circuits by using the same paradigms as the dominant electronics industry. After twenty years of fervid development, silicon photonics is entering the market with low cost, high performance and mass-manufacturable optical devices. Until now, most silicon photonic devices have been based on linear optical effects, despite the many phenomenologies associated with nonlinear optics in both bulk materials and integrated waveguides. Silicon and silicon-based materials have strong optical nonlinearities which are enhanced in integrated devices by the small cross-section of the high-index contrast silicon waveguides or photonic crystals. Here the photons are made to strongly interact with the medium where they propagate. This is the central argument of nonlinear silicon photonics. It is the aim of this review to describe the state-of-the-art in the field. Starting from the basic nonlinearities in a silicon waveguide or in optical resonator geometries, many phenomena and applications are described—including frequency generation, frequency conversion, frequency-comb generation, supercontinuum generation, soliton formation, temporal imaging and time lensing, Raman lasing, and comb spectroscopy. Emerging quantum photonics applications, such as entangled photon sources, heralded single-photon sources and integrated quantum photonic circuits are also addressed at the end of this review.

  15. Silicon germanium mask for deep silicon etching

    KAUST Repository

    Serry, Mohamed

    2014-07-29

    Polycrystalline silicon germanium (SiGe) can offer excellent etch selectivity to silicon during cryogenic deep reactive ion etching in an SF.sub.6/O.sub.2 plasma. Etch selectivity of over 800:1 (Si:SiGe) may be achieved at etch temperatures from -80 degrees Celsius to -140 degrees Celsius. High aspect ratio structures with high resolution may be patterned into Si substrates using SiGe as a hard mask layer for construction of microelectromechanical systems (MEMS) devices and semiconductor devices.

  16. Silicon germanium mask for deep silicon etching

    KAUST Repository

    Serry, Mohamed; Rubin, Andrew; Refaat, Mohamed; Sedky, Sherif; Abdo, Mohammad

    2014-01-01

    Polycrystalline silicon germanium (SiGe) can offer excellent etch selectivity to silicon during cryogenic deep reactive ion etching in an SF.sub.6/O.sub.2 plasma. Etch selectivity of over 800:1 (Si:SiGe) may be achieved at etch temperatures from -80 degrees Celsius to -140 degrees Celsius. High aspect ratio structures with high resolution may be patterned into Si substrates using SiGe as a hard mask layer for construction of microelectromechanical systems (MEMS) devices and semiconductor devices.

  17. Improved Catalysts for Heavy Oil Upgrading Based on Zeolite Y Nanoparticles Encapsulated Stable Nanoporous Host

    Energy Technology Data Exchange (ETDEWEB)

    Conrad Ingram; Mark Mitchell

    2007-09-30

    The objective of this project is to synthesize nanocrystals of highly acidic zeolite Y nanoclusters, encapsulate them within the channels of mesoporous (nanoporous) silicates or nanoporous organosilicates, and evaluate the 'zeolite Y/Nanoporous host' composites as catalysts for the upgrading of heavy petroleum feedstocks. In comparison to conventionally-used zeolite Y catalysts of micron size particles, the nanocrystals (< 100 nm particle size) which contain shorter path lengths, are expected to allow faster diffusion of large hydrocarbon substrates and the catalysis products within and out of the zeolite's channels and cages (<1 nm size). This is expected to significantly reduce deactivation of the catalyst and to prolong their period of reactivity. Encapsulating zeolite Y nanocrystals within the nanoporous materials is expected to protect its external surfaces and pore entrances from being blocked by large hydrocarbon substrates, since these substrates will initially be converted to small molecules by the nanoporous host (a catalyst in its own right). The project consisted of four major tasks as follows: (1) synthesis of the nanoparticles of zeolite Y (of various chemical compositions) using various techniques such as the addition of organic additives to conventional zeolite Y synthesis mixtures to suppress zeolite Y crystal growth; (2) synthesis of nanoporous silicate host materials of up to 30 nm pore diameter, using poly (alkylene oxide) copolymers which when removed will yield a mesoporous material; (3) synthesis of zeolite Y/Nanoporous Host composite materials as potential catalysts; and (4) evaluation of the catalyst for the upgrading of heavy petroleum feedstocks.

  18. Fabrication and textural characterization of nanoporous carbon electrodes embedded with CuO nanoparticles for supercapacitors

    Energy Technology Data Exchange (ETDEWEB)

    Prasad, Kumaresa P S; Dhawale, Dattatray S; Ariga, Katsuhiko; Vinu, Ajayan [International Center for Materials Nanoarchitectonics (MANA), World Premier International (WPI) Research Center, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Sivakumar, Thiripuranthagan [Department of Chemical Engineering, Anna University, Gundy, Chennai 600025 (India); Aldeyab, Salem S [Department of Chemistry, Petrochemicals Research Chair, Faculty of Science, King Saud University, PO Box 2455 Riyadh 11451 (Saudi Arabia); Zaidi, Javaid S M, E-mail: vinu.ajayan@nims.go.jp [Department of Chemical Engineering, King Fahd University of Petroleum and Minerals, Dhahran 31261 (Saudi Arabia)

    2011-08-15

    We introduce a novel strategy of fabricating nanoporous carbons loaded with different amounts of CuO nanoparticles via a hard templating approach, using copper-containing mesoporous silica as the template and sucrose as the carbon source. The nature and dispersion of the CuO nanoparticles on the surface of the nanoporous carbons were investigated by x-ray diffraction (XRD), high-resolution scanning electron microscopy (HRSEM) and high-resolution transmission electron microscopy (HRTEM). XRD results reveal that nanoporous carbons with embedded CuO nanoparticles exhibit a well-ordered mesoporous structure, whereas the nitrogen adsorption measurements indicate the presence of excellent textural characteristics such as high surface area, large pore volume and uniform pore size distribution. The amount of CuO nanoparticles in the nanochannels of the nanoporous carbon could be controlled by simply varying the Si/Cu molar ratio of the mesoporous silica template. Morphological characterization by SEM and TEM reveals that high-quality CuO nanoparticles are distributed homogeneously within the nanoporous carbon framework. The supercapacitance behavior of the CuO-loaded nanoporous carbons was investigated. The material with a small amount of CuO in the mesochannels and high surface area affords a maximum specific capacitance of 300 F g{sup -1} at a 20 mV s{sup -1} scan rate in an aqueous electrolyte solution. A supercapacitor containing the CuO-loaded nanoporous carbon is highly stable and exhibits a long cycle life with 91% specific capacitance retained after 1000 cycles.

  19. Fabrication and textural characterization of nanoporous carbon electrodes embedded with CuO nanoparticles for supercapacitors

    Science.gov (United States)

    Prasad, Kumaresa P. S.; Dhawale, Dattatray S.; Sivakumar, Thiripuranthagan; Aldeyab, Salem S.; Zaidi, Javaid S. M.; Ariga, Katsuhiko; Vinu, Ajayan

    2011-08-01

    We introduce a novel strategy of fabricating nanoporous carbons loaded with different amounts of CuO nanoparticles via a hard templating approach, using copper-containing mesoporous silica as the template and sucrose as the carbon source. The nature and dispersion of the CuO nanoparticles on the surface of the nanoporous carbons were investigated by x-ray diffraction (XRD), high-resolution scanning electron microscopy (HRSEM) and high-resolution transmission electron microscopy (HRTEM). XRD results reveal that nanoporous carbons with embedded CuO nanoparticles exhibit a well-ordered mesoporous structure, whereas the nitrogen adsorption measurements indicate the presence of excellent textural characteristics such as high surface area, large pore volume and uniform pore size distribution. The amount of CuO nanoparticles in the nanochannels of the nanoporous carbon could be controlled by simply varying the Si/Cu molar ratio of the mesoporous silica template. Morphological characterization by SEM and TEM reveals that high-quality CuO nanoparticles are distributed homogeneously within the nanoporous carbon framework. The supercapacitance behavior of the CuO-loaded nanoporous carbons was investigated. The material with a small amount of CuO in the mesochannels and high surface area affords a maximum specific capacitance of 300 F g-1 at a 20 mV s-1 scan rate in an aqueous electrolyte solution. A supercapacitor containing the CuO-loaded nanoporous carbon is highly stable and exhibits a long cycle life with 91% specific capacitance retained after 1000 cycles.

  20. Fabrication and textural characterization of nanoporous carbon electrodes embedded with CuO nanoparticles for supercapacitors

    Directory of Open Access Journals (Sweden)

    Kumaresa P S Prasad, Dattatray S Dhawale, Thiripuranthagan Sivakumar, Salem S Aldeyab, Javaid S M Zaidi, Katsuhiko Ariga and Ajayan Vinu

    2011-01-01

    Full Text Available We introduce a novel strategy of fabricating nanoporous carbons loaded with different amounts of CuO nanoparticles via a hard templating approach, using copper-containing mesoporous silica as the template and sucrose as the carbon source. The nature and dispersion of the CuO nanoparticles on the surface of the nanoporous carbons were investigated by x-ray diffraction (XRD, high-resolution scanning electron microscopy (HRSEM and high-resolution transmission electron microscopy (HRTEM. XRD results reveal that nanoporous carbons with embedded CuO nanoparticles exhibit a well-ordered mesoporous structure, whereas the nitrogen adsorption measurements indicate the presence of excellent textural characteristics such as high surface area, large pore volume and uniform pore size distribution. The amount of CuO nanoparticles in the nanochannels of the nanoporous carbon could be controlled by simply varying the Si/Cu molar ratio of the mesoporous silica template. Morphological characterization by SEM and TEM reveals that high-quality CuO nanoparticles are distributed homogeneously within the nanoporous carbon framework. The supercapacitance behavior of the CuO-loaded nanoporous carbons was investigated. The material with a small amount of CuO in the mesochannels and high surface area affords a maximum specific capacitance of 300 F g-1 at a 20 mV s-1 scan rate in an aqueous electrolyte solution. A supercapacitor containing the CuO-loaded nanoporous carbon is highly stable and exhibits a long cycle life with 91% specific capacitance retained after 1000 cycles.

  1. Process for making silicon

    Science.gov (United States)

    Levin, Harry (Inventor)

    1987-01-01

    A reactor apparatus (10) adapted for continuously producing molten, solar grade purity elemental silicon by thermal reaction of a suitable precursor gas, such as silane (SiH.sub.4), is disclosed. The reactor apparatus (10) includes an elongated reactor body (32) having graphite or carbon walls which are heated to a temperature exceeding the melting temperature of silicon. The precursor gas enters the reactor body (32) through an efficiently cooled inlet tube assembly (22) and a relatively thin carbon or graphite septum (44). The septum (44), being in contact on one side with the cooled inlet (22) and the heated interior of the reactor (32) on the other side, provides a sharp temperature gradient for the precursor gas entering the reactor (32) and renders the operation of the inlet tube assembly (22) substantially free of clogging. The precursor gas flows in the reactor (32) in a substantially smooth, substantially axial manner. Liquid silicon formed in the initial stages of the thermal reaction reacts with the graphite or carbon walls to provide a silicon carbide coating on the walls. The silicon carbide coated reactor is highly adapted for prolonged use for production of highly pure solar grade silicon. Liquid silicon (20) produced in the reactor apparatus (10) may be used directly in a Czochralski or other crystal shaping equipment.

  2. Hydrogen in amorphous silicon

    International Nuclear Information System (INIS)

    Peercy, P.S.

    1980-01-01

    The structural aspects of amorphous silicon and the role of hydrogen in this structure are reviewed with emphasis on ion implantation studies. In amorphous silicon produced by Si ion implantation of crystalline silicon, the material reconstructs into a metastable amorphous structure which has optical and electrical properties qualitatively similar to the corresponding properties in high-purity evaporated amorphous silicon. Hydrogen studies further indicate that these structures will accomodate less than or equal to 5 at.% hydrogen and this hydrogen is bonded predominantly in a monohydride (SiH 1 ) site. Larger hydrogen concentrations than this can be achieved under certain conditions, but the excess hydrogen may be attributed to defects and voids in the material. Similarly, glow discharge or sputter deposited amorphous silicon has more desirable electrical and optical properties when the material is prepared with low hydrogen concentration and monohydride bonding. Results of structural studies and hydrogen incorporation in amorphous silicon were discussed relative to the different models proposed for amorphous silicon

  3. Transformational silicon electronics

    KAUST Repository

    Rojas, Jhonathan Prieto

    2014-02-25

    In today\\'s traditional electronics such as in computers or in mobile phones, billions of high-performance, ultra-low-power devices are neatly integrated in extremely compact areas on rigid and brittle but low-cost bulk monocrystalline silicon (100) wafers. Ninety percent of global electronics are made up of silicon. Therefore, we have developed a generic low-cost regenerative batch fabrication process to transform such wafers full of devices into thin (5 μm), mechanically flexible, optically semitransparent silicon fabric with devices, then recycling the remaining wafer to generate multiple silicon fabric with chips and devices, ensuring low-cost and optimal utilization of the whole substrate. We show monocrystalline, amorphous, and polycrystalline silicon and silicon dioxide fabric, all from low-cost bulk silicon (100) wafers with the semiconductor industry\\'s most advanced high-κ/metal gate stack based high-performance, ultra-low-power capacitors, field effect transistors, energy harvesters, and storage to emphasize the effectiveness and versatility of this process to transform traditional electronics into flexible and semitransparent ones for multipurpose applications. © 2014 American Chemical Society.

  4. Silicon micromachined vibrating gyroscopes

    Science.gov (United States)

    Voss, Ralf

    1997-09-01

    This work gives an overview of silicon micromachined vibrating gyroscopes. Market perspectives and fields of application are pointed out. The advantage of using silicon micromachining is discussed and estimations of the desired performance, especially for automobiles are given. The general principle of vibrating gyroscopes is explained. Vibrating silicon gyroscopes can be divided into seven classes. for each class the characteristic principle is presented and examples are given. Finally a specific sensor, based on a tuning fork for automotive applications with a sensitivity of 250(mu) V/degrees is described in detail.

  5. Porous silicon gettering

    Energy Technology Data Exchange (ETDEWEB)

    Tsuo, Y.S.; Menna, P.; Pitts, J.R. [National Renewable Energy Lab., Golden, CO (United States)] [and others

    1996-05-01

    The authors have studied a novel extrinsic gettering method that uses the large surface areas produced by a porous-silicon etch as gettering sites. The annealing step of the gettering used a high-flux solar furnace. They found that a high density of photons during annealing enhanced the impurity diffusion to the gettering sites. The authors used metallurgical-grade Si (MG-Si) prepared by directional solidification casing as the starting material. They propose to use porous-silicon-gettered MG-Si as a low-cost epitaxial substrate for polycrystalline silicon thin-film growth.

  6. Silicon etch process

    International Nuclear Information System (INIS)

    Day, D.J.; White, J.C.

    1984-01-01

    A silicon etch process wherein an area of silicon crystal surface is passivated by radiation damage and non-planar structure produced by subsequent anisotropic etching. The surface may be passivated by exposure to an energetic particle flux - for example an ion beam from an arsenic, boron, phosphorus, silicon or hydrogen source, or an electron beam. Radiation damage may be used for pattern definition and/or as an etch stop. Ethylenediamine pyrocatechol or aqueous potassium hydroxide anisotropic etchants may be used. The radiation damage may be removed after etching by thermal annealing. (author)

  7. Silicon integrated circuit process

    International Nuclear Information System (INIS)

    Lee, Jong Duck

    1985-12-01

    This book introduces the process of silicon integrated circuit. It is composed of seven parts, which are oxidation process, diffusion process, ion implantation process such as ion implantation equipment, damage, annealing and influence on manufacture of integrated circuit and device, chemical vapor deposition process like silicon Epitaxy LPCVD and PECVD, photolithography process, including a sensitizer, spin, harden bake, reflection of light and problems related process, infrared light bake, wet-etch, dry etch, special etch and problems of etching, metal process like metal process like metal-silicon connection, aluminum process, credibility of aluminum and test process.

  8. Silicon integrated circuit process

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jong Duck

    1985-12-15

    This book introduces the process of silicon integrated circuit. It is composed of seven parts, which are oxidation process, diffusion process, ion implantation process such as ion implantation equipment, damage, annealing and influence on manufacture of integrated circuit and device, chemical vapor deposition process like silicon Epitaxy LPCVD and PECVD, photolithography process, including a sensitizer, spin, harden bake, reflection of light and problems related process, infrared light bake, wet-etch, dry etch, special etch and problems of etching, metal process like metal process like metal-silicon connection, aluminum process, credibility of aluminum and test process.

  9. Silicon nanowire hybrid photovoltaics

    KAUST Repository

    Garnett, Erik C.; Peters, Craig; Brongersma, Mark; Cui, Yi; McGehee, Mike

    2010-01-01

    Silicon nanowire Schottky junction solar cells have been fabricated using n-type silicon nanowire arrays and a spin-coated conductive polymer (PEDOT). The polymer Schottky junction cells show superior surface passivation and open-circuit voltages compared to standard diffused junction cells with native oxide surfaces. External quantum efficiencies up to 88% were measured for these silicon nanowire/PEDOT solar cells further demonstrating excellent surface passivation. This process avoids high temperature processes which allows for low-cost substrates to be used. © 2010 IEEE.

  10. Silicon nanowire hybrid photovoltaics

    KAUST Repository

    Garnett, Erik C.

    2010-06-01

    Silicon nanowire Schottky junction solar cells have been fabricated using n-type silicon nanowire arrays and a spin-coated conductive polymer (PEDOT). The polymer Schottky junction cells show superior surface passivation and open-circuit voltages compared to standard diffused junction cells with native oxide surfaces. External quantum efficiencies up to 88% were measured for these silicon nanowire/PEDOT solar cells further demonstrating excellent surface passivation. This process avoids high temperature processes which allows for low-cost substrates to be used. © 2010 IEEE.

  11. Joining elements of silicon carbide

    International Nuclear Information System (INIS)

    Olson, B.A.

    1979-01-01

    A method of joining together at least two silicon carbide elements (e.g.in forming a heat exchanger) is described, comprising subjecting to sufficiently non-oxidizing atmosphere and sufficiently high temperature, material placed in space between the elements. The material consists of silicon carbide particles, carbon and/or a precursor of carbon, and silicon, such that it forms a joint joining together at least two silicon carbide elements. At least one of the elements may contain silicon. (author)

  12. Generation of nanopores during desorption of NH3 from Mg(NH3)6Cl2

    DEFF Research Database (Denmark)

    Hummelshøj, Jens Strabo; Sørensen, Rasmus Zink; Kostova, M.Y.

    2006-01-01

    It is shown that nanopores are formed during desorption of NH3 from Mg(NH3)6Cl2, which has been proposed as a hydrogen storage material. The system of nanopores facilitates the transport of desorbed ammonia away from the interior of large volumes of compacted storage material. DFT calculations sh...

  13. An accurate and rapid continuous wavelet dynamic time warping algorithm for unbalanced global mapping in nanopore sequencing

    KAUST Repository

    Han, Renmin; Li, Yu; Wang, Sheng; Gao, Xin

    2017-01-01

    Long-reads, point-of-care, and PCR-free are the promises brought by nanopore sequencing. Among various steps in nanopore data analysis, the global mapping between the raw electrical current signal sequence and the expected signal sequence from

  14. Micropatterning of a nanoporous alumina membrane with poly(ethylene glycol) hydrogel to create cellular micropatterns on nanotopographic substrates.

    Science.gov (United States)

    Lee, Hyun Jong; Kim, Dae Nyun; Park, Saemi; Lee, Yeol; Koh, Won-Gun

    2011-03-01

    In this paper, we describe a simple method for fabricating micropatterned nanoporous substrates that are capable of controlling the spatial positioning of mammalian cells. Micropatterned substrates were prepared by fabricating poly(ethylene glycol) (PEG) hydrogel microstructures on alumina membranes with 200 nm nanopores using photolithography. Because hydrogel precursor solution could infiltrate and become crosslinked within the nanopores, the resultant hydrogel micropatterns were firmly anchored on the substrate without the use of adhesion-promoting monolayers, thereby allow tailoring of the surface properties of unpatterned nanoporous areas. For mammalian cell patterning, arrays of microwells of different dimensions were fabricated. These microwells were composed of hydrophilic PEG hydrogel walls surrounding nanoporous bottoms that were modified with cell-adhesive Arg-Gly-Asp (RGD) peptides. Because the PEG hydrogel was non-adhesive towards proteins and cells, cells adhered selectively and remained viable within the RGD-modified nanoporous regions, thereby creating cellular micropatterns. Although the morphology of cell clusters and the number of cells inside one microwell were dependent on the lateral dimension of the microwells, adhered cells that were in direct contact with nanopores were able to penetrate into the nanopores by small extensions (filopodia) for all the different sizes of microwells evaluated. Copyright © 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  15. Urea impedimetric biosensor based on reactive RF magnetron sputtered zinc oxide nanoporous transducer

    International Nuclear Information System (INIS)

    Mozaffari, Sayed Ahmad; Rahmanian, Reza; Abedi, Mohammad; Amoli, Hossein Salar

    2014-01-01

    Graphical abstract: - Highlights: • Application and optimization of reactive RF magnetron sputtering for homogeneous nanoporous ZnO thin film formation. • Exploiting nanoporous ZnO thin film as a good porous framework with large surface area/volume for having stable immobilized enzyme with minimum loss of activity. • Application of impedimetric assessment for urea biosensing due to its rapidity, sensitivity, and repeatability. - Abstract: Uniform sputtered nanoporous zinc oxide (Nano-ZnO) thin film on the conductive fluorinated-tin oxide (FTO) layer was applied to immobilize urease enzyme (Urs) for urea detection. Highly uniform nanoporous ZnO thin film were obtained by reactive radio frequency (RF) magnetron sputtering system at the optimized instrumental deposition conditions. Characterization of the surface morphology and roughness of ZnO thin film by field emission-scanning electron microscopy (FE-SEM) exhibits cavities of nanoporous film as an effective biosensing area for enzyme immobilization. Step by step monitoring of FTO/Nano-ZnO/Urs biosensor fabrication were performed using electrochemical methods such as cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques. Fabricated FTO/Nano-ZnO/Urs biosensor was used for urea determination using EIS experiments. The impedimetric results show high sensitivity for urea detection within 0.83–23.24 mM and limit of detection as 0.40 mM

  16. Electronic thermal conductivity of 2-dimensional circular-pore metallic nanoporous materials

    International Nuclear Information System (INIS)

    Huang, Cong-Liang; Lin, Zi-Zhen; Luo, Dan-Chen; Huang, Zun

    2016-01-01

    The electronic thermal conductivity (ETC) of 2-dimensional circular-pore metallic nanoporous material (MNM) was studied here for its possible applications in thermal cloaks. A simulation method based on the free-electron-gas model was applied here without considering the quantum effects. For the MNM with circular nanopores, there is an appropriate nanopore size for thermal conductivity tuning, while a linear relationship exists for this size between the ETC and the porosity. The appropriate nanopore diameter size will be about one times that of the electron mean free path. The ETC difference along different directions would be less than 10%, which is valuable when estimating possible errors, because the nanoscale-material direction could not be controlled during its application. Like nanoparticles, the ETC increases with increasing pore size (diameter for nanoparticles) while the porosity was fixed, until the pore size reaches about four times that of electron mean free path, at which point the ETC plateaus. The specular coefficient on the surface will significantly impact the ETC, especially for a high-porosity MNM. The ETC can be decreased by 30% with a tuning specular coefficient. - Highlights: • For metallic nanoporous materials, there is an appropriate pore size for thermal conductivity tuning. • ETC increases with increasing pore size until pore size reaches about four times EMFP. • The ETC difference between different directions will be less than 10%. • The ETC can be decreased by 30% with tuning specular coefficient.

  17. Instrumentation for low noise nanopore-based ionic current recording under laser illumination

    Science.gov (United States)

    Roelen, Zachary; Bustamante, José A.; Carlsen, Autumn; Baker-Murray, Aidan; Tabard-Cossa, Vincent

    2018-01-01

    We describe a nanopore-based optofluidic instrument capable of performing low-noise ionic current recordings of individual biomolecules under laser illumination. In such systems, simultaneous optical measurements generally introduce significant parasitic noise in the electrical signal, which can severely reduce the instrument sensitivity, critically hindering the monitoring of single-molecule events in the ionic current traces. Here, we present design rules and describe simple adjustments to the experimental setup to mitigate the different noise sources encountered when integrating optical components to an electrical nanopore system. In particular, we address the contributions to the electrical noise spectra from illuminating the nanopore during ionic current recording and mitigate those effects through control of the illumination source and the use of a PDMS layer on the SiNx membrane. We demonstrate the effectiveness of our noise minimization strategies by showing the detection of DNA translocation events during membrane illumination with a signal-to-noise ratio of ˜10 at 10 kHz bandwidth. The instrumental guidelines for noise minimization that we report are applicable to a wide range of nanopore-based optofluidic systems and offer the possibility of enhancing the quality of synchronous optical and electrical signals obtained during single-molecule nanopore-based analysis.

  18. Protein Nanopore-Based Discrimination between Selected Neutral Amino Acids from Polypeptides.

    Science.gov (United States)

    Asandei, Alina; Rossini, Aldo E; Chinappi, Mauro; Park, Yoonkyung; Luchian, Tudor

    2017-12-19

    Nanopore probing of biological polymers has the potential to achieve single-molecule sequencing at low cost, high throughput, portability, and minimal sample preparation and apparatus. In this article, we explore the possibility of discrimination between neutral amino acid residues from the primary structure of 30 amino acids long, engineered peptides, through the analysis of single-molecule ionic current fluctuations accompanying their slowed-down translocation across the wild type α-hemolysin (α-HL) nanopore, and molecular dynamics simulations. We found that the transient presence inside the α-HL of alanine or tryptophan residues from the primary sequence of engineered peptides results in distinct features of the ionic current fluctuation pattern associated with the peptide reversibly blocking the nanopore. We propose that α-HL sensitivity to the molecular exclusion at the most constricted region mediates ionic current blockade events correlated with the volumes that are occluded by at least three alanine or tryptophan residues, and provides the specificity needed to discriminate between groups of neutral amino acids. Further, we find that the pattern of current fluctuations depends on the orientation of the threaded amino acid residues, suggestive of a conformational anisotropy of the ensemble of conformations of the peptide on the restricted nanopore region, related to its relative axial orientation inside the nanopore.

  19. Davisson-Germer Prize Talk: Hydrogen storage in nanoporous materials

    Science.gov (United States)

    Chabal, Yves

    2009-03-01

    To develop a hydrogen-based energy technology, several classes of materials are being considered to achieve the DOE targets for gravimetric and volumetric hydrogen densities for hydrogen storage, including liquids (e.g. ammonium borohydrides), clathrate structures, complex metal hydrides, nanostructured (e.g. carbon) an nanoporous materials. Fundamental studies are necessary to determine the ultimate hydrogen capacity of each system. Nanoporous Metal-organic Framework (MOF) materials are promising candidates for hydrogen storage because the chemical nature and size of their unit cell can be tailored to weakly attract and incorporate H2 molecules, with good volumetric and mass density. In this talk, we consider the structure M2(BDC)2(TED), where M is a metal atom (Zn, Ni, Cu), BDC is benzenedicarboxylate and TED triethylenediamine, to determine the location and interaction of H2 molecules within the MOF. These compounds are isostructural and crystallize in the tetragonal phase (space group P4/ncc), they construct 3D porous structures with relatively large pore size (˜7-8 A ), pore volume (˜0.63-0.84 cc/g) and BET surface area (˜1500-1900 m^2/g). At high pressures (300-800 psi), the perturbation of the H-H stretching mode can be measured with IR absorption spectroscopy, showing a 35 cm-1 redshift from the unperturbed ortho (4155 cm-1 ) and para (4161 cm-1 ) frequencies. Using a newly developed non empirical van der Waals DFT method vdW-DFT),ootnotetextJ.Y. Lee, D.H. Olson, L. Pan, T.J. Emge, J. Li, Adv. Func. Mater. 17, 1255 (2007) it can be shown that the locus of the deepest H2 binding positions lies within to types of narrow channels. The energies of the most stable binding sites, as well as the number of such binding sites, are consistent with the values obtained from experimental adsorption isotherms, and heat of adsorption) data.ootnotetextM. Dion, H. Ryberg, E. Schroder, D. C. Langreth, B.I. Lundqvist, Phys. Rev. Lett. 92, 246401 (2004). Importantly, the

  20. Multiply Surface-Functionalized Nanoporous Carbon for Vehicular Hydrogen Storage

    Energy Technology Data Exchange (ETDEWEB)

    Pfeifer, Peter [Univ. of Missouri, Columbia, MO (United States). Dept. of Physics; Gillespie, Andrew [Univ. of Missouri, Columbia, MO (United States). Dept. of Physics; Stalla, David [Univ. of Missouri, Columbia, MO (United States). Dept. of Physics; Dohnke, Elmar [Univ. of Missouri, Columbia, MO (United States). Dept. of Physics

    2017-02-20

    The purpose of the project “Multiply Surface-Functionalized Nanoporous Carbon for Vehicular Hydrogen Storage” is the development of materials that store hydrogen (H2) by adsorption in quantities and at conditions that outperform current compressed-gas H2 storage systems for electric power generation from hydrogen fuel cells (HFCs). Prominent areas of interest for HFCs are light-duty vehicles (“hydrogen cars”) and replacement of batteries with HFC systems in a wide spectrum of applications, ranging from forklifts to unmanned areal vehicles to portable power sources. State-of-the-art compressed H2 tanks operate at pressures between 350 and 700 bar at ambient temperature and store 3-4 percent of H2 by weight (wt%) and less than 25 grams of H2 per liter (g/L) of tank volume. Thus, the purpose of the project is to engineer adsorbents that achieve storage capacities better than compressed H2 at pressures less than 350 bar. Adsorption holds H2 molecules as a high-density film on the surface of a solid at low pressure, by virtue of attractive surface-gas interactions. At a given pressure, the density of the adsorbed film is the higher the stronger the binding of the molecules to the surface is (high binding energies). Thus, critical for high storage capacities are high surface areas, high binding energies, and low void fractions (high void fractions, such as in interstitial space between adsorbent particles, “waste” storage volume by holding hydrogen as non-adsorbed gas). Coexistence of high surface area and low void fraction makes the ideal adsorbent a nanoporous monolith, with pores wide enough to hold high-density hydrogen films, narrow enough to minimize storage as non-adsorbed gas, and thin walls between pores to minimize the volume occupied by solid instead of hydrogen. A monolith can be machined to fit into a rectangular tank (low pressure, conformable tank), cylindrical tank

  1. Superconducting nanowire networks formed on nanoporous membrane substrates

    Science.gov (United States)

    Luo, Qiong

    Introducing a regular array of holes into superconducting thin films has been actively pursued to stabilize and pin the vortex lattice against external driving forces, enabling higher current capabilities. If the width of the sections between neighboring holes is comparable to the superconducting coherence length, the circulation of the Cooper pairs in around the holes in the presence of a magnetic field can also produce the Little-Parks effect, i.e. periodic oscillation of the critical temperature. These two mechanisms, commensurate vortex pinning enhancement by the hole-array and the critical temperature oscillations of a wire network due to Little-Parks effect can induce similar experimental observations such as magnetoresistance oscillation and enhancement of the critical current at specific magnetic fields. This dissertation work investigates the effect of a hole-array on the properties of superconducting films deposited onto nanoporous substrates. Experiments on anisotropies of the critical temperature for niobium films on anodic aluminum oxide membrane substrates containing a regular hole-array reveal that the critical temperature exhibits two strong anisotropic effects: Little-Parks oscillations whose period varies with field direction superimposed on a smooth background arising from one dimensional confinement by the finite lateral space between neighboring holes. The two components of the anisotropy are intrinsically linked and appear in concert. That is, the hole-array changes the dimensionality of a two-dimensional (2D) film to a network of 1D nanowire network. Network of superconducting nanowires with transverse dimensions as small as few nanometers were achieved by coating molybdenum germanium (MoGe) layer onto commercially available filtration membranes which have extremely dense nanopores. The magnetoresistance, magnetic field dependence of the critical temperature and the anisotropies of the synthesized MoGe nanowire networks can be consistently

  2. Nanoporous gold membranes: From morphological control to fuel cell catalysis

    Science.gov (United States)

    Ding, Yi

    Porous noble metals are particularly attractive for scientific research and industrial applications such as catalysis, sensing, and filtration. In this thesis, I will discuss the fabrication, characterization, and application of a new class of porous metals, called nanoporous metals (NPM). NPM is made during selective dissolution (also called dealloying) of reactive components (e.g., silver) from multi-component alloys (e.g., Ag/Au alloy). Commercially available white gold leaf (Ag65Au35) can, for example, be etched into nanoporous gold (NPG) membrane by simply floating the leaf on concentrated nitric acid for periods of a few minutes. NPG leaf adopts a single crystal porous structure within individual grains. The microstructure of NPG, such as the pore size, is tunable between a few nanometers to sub-micron length scale by either thermal annealing or post-treatment in nitric acid for extended period of time. A new gas-liquid-solid interface electroless plating technique is developed to uniformly cover the NPG surface with other metals, such as silver and platinum. This technique allows new opportunities of making functionalized nanostructures. We show that a combination of silver plating and dealloying can be used to make multimodal porous metals, which are expected to have application in sensing field. Electroless platinum plating onto NPG shows very usual growth mode. TEM observation indicates that the platinum layer on NPG surface takes a novel form of layer-islanding growth (Stranski-Krastanov growth). Annealing the Pt/NPG composite smoothens the Pt islands and forms a 1 nm coherent Pt layer on the NPG backbone, possibly with dislocation formation at the Pt/Au interface. Furthermore, it was found that we could dissolve the gold away in aqueous gold etchant, leaving behind the 1 nm-thick Pt shell, a structure we call nanotubular mesoporous platinum (NMP). Pt plated NPG has a series of unique structural properties, such as high active surface area, thermally

  3. Photoluminescence and electrical properties of silicon oxide and silicon nitride superlattices containing silicon nanocrystals

    International Nuclear Information System (INIS)

    Shuleiko, D V; Ilin, A S

    2016-01-01

    Photoluminescence and electrical properties of superlattices with thin (1 to 5 nm) alternating silicon-rich silicon oxide or silicon-rich silicon nitride, and silicon oxide or silicon nitride layers containing silicon nanocrystals prepared by plasma-enhanced chemical vapor deposition with subsequent annealing were investigated. The entirely silicon oxide based superlattices demonstrated photoluminescence peak shift due to quantum confinement effect. Electrical measurements showed the hysteresis effect in the vicinity of zero voltage due to structural features of the superlattices from SiOa 93 /Si 3 N 4 and SiN 0 . 8 /Si 3 N 4 layers. The entirely silicon nitride based samples demonstrated resistive switching effect, comprising an abrupt conductivity change at about 5 to 6 V with current-voltage characteristic hysteresis. The samples also demonstrated efficient photoluminescence with maximum at ∼1.4 eV, due to exiton recombination in silicon nanocrystals. (paper)

  4. Advances in silicon nanophotonics

    DEFF Research Database (Denmark)

    Hvam, Jørn Märcher; Pu, Minhao

    Silicon has long been established as an ideal material for passive integrated optical circuitry due to its high refractive index, with corresponding strong optical confinement ability, and its low-cost CMOS-compatible manufacturability. However, the inversion symmetry of the silicon crystal lattice.......g. in high-bit-rate optical communication circuits and networks, it is vital that the nonlinear optical effects of silicon are being strongly enhanced. This can among others be achieved in photonic-crystal slow-light waveguides and in nano-engineered photonic-wires (Fig. 1). In this talk I shall present some...... recent advances in this direction. The efficient coupling of light between optical fibers and the planar silicon devices and circuits is of crucial importance. Both end-coupling (Fig. 1) and grating-coupling solutions will be discussed along with polarization issues. A new scheme for a hybrid III...

  5. Integrated silicon optoelectronics

    CERN Document Server

    Zimmermann, Horst

    2000-01-01

    'Integrated Silicon Optoelectronics'assembles optoelectronics and microelectronics The book concentrates on silicon as the major basis of modern semiconductor devices and circuits Starting from the basics of optical emission and absorption and from the device physics of photodetectors, the aspects of the integration of photodetectors in modern bipolar, CMOS, and BiCMOS technologies are discussed Detailed descriptions of fabrication technologies and applications of optoelectronic integrated circuits are included The book, furthermore, contains a review of the state of research on eagerly expected silicon light emitters In order to cover the topic of the book comprehensively, integrated waveguides, gratings, and optoelectronic power devices are included in addition Numerous elaborate illustrations promote an easy comprehension 'Integrated Silicon Optoelectronics'will be of value to engineers, physicists, and scientists in industry and at universities The book is also recommendable for graduate students speciali...

  6. Silicon microfabricated beam expander

    International Nuclear Information System (INIS)

    Othman, A.; Ibrahim, M. N.; Hamzah, I. H.; Sulaiman, A. A.; Ain, M. F.

    2015-01-01

    The feasibility design and development methods of silicon microfabricated beam expander are described. Silicon bulk micromachining fabrication technology is used in producing features of the structure. A high-precision complex 3-D shape of the expander can be formed by exploiting the predictable anisotropic wet etching characteristics of single-crystal silicon in aqueous Potassium-Hydroxide (KOH) solution. The beam-expander consist of two elements, a micromachined silicon reflector chamber and micro-Fresnel zone plate. The micro-Fresnel element is patterned using lithographic methods. The reflector chamber element has a depth of 40 µm, a diameter of 15 mm and gold-coated surfaces. The impact on the depth, diameter of the chamber and absorption for improved performance are discussed

  7. Silicon microfabricated beam expander

    Science.gov (United States)

    Othman, A.; Ibrahim, M. N.; Hamzah, I. H.; Sulaiman, A. A.; Ain, M. F.

    2015-03-01

    The feasibility design and development methods of silicon microfabricated beam expander are described. Silicon bulk micromachining fabrication technology is used in producing features of the structure. A high-precision complex 3-D shape of the expander can be formed by exploiting the predictable anisotropic wet etching characteristics of single-crystal silicon in aqueous Potassium-Hydroxide (KOH) solution. The beam-expander consist of two elements, a micromachined silicon reflector chamber and micro-Fresnel zone plate. The micro-Fresnel element is patterned using lithographic methods. The reflector chamber element has a depth of 40 µm, a diameter of 15 mm and gold-coated surfaces. The impact on the depth, diameter of the chamber and absorption for improved performance are discussed.

  8. Silicon microfabricated beam expander

    Energy Technology Data Exchange (ETDEWEB)

    Othman, A., E-mail: aliman@ppinang.uitm.edu.my; Ibrahim, M. N.; Hamzah, I. H.; Sulaiman, A. A. [Faculty of Electrical Engineering, Universiti Teknologi MARA Malaysia, 40450, Shah Alam, Selangor (Malaysia); Ain, M. F. [School of Electrical and Electronic Engineering, Engineering Campus, Universiti Sains Malaysia, Seri Ampangan, 14300,Nibong Tebal, Pulau Pinang (Malaysia)

    2015-03-30

    The feasibility design and development methods of silicon microfabricated beam expander are described. Silicon bulk micromachining fabrication technology is used in producing features of the structure. A high-precision complex 3-D shape of the expander can be formed by exploiting the predictable anisotropic wet etching characteristics of single-crystal silicon in aqueous Potassium-Hydroxide (KOH) solution. The beam-expander consist of two elements, a micromachined silicon reflector chamber and micro-Fresnel zone plate. The micro-Fresnel element is patterned using lithographic methods. The reflector chamber element has a depth of 40 µm, a diameter of 15 mm and gold-coated surfaces. The impact on the depth, diameter of the chamber and absorption for improved performance are discussed.

  9. Porous Silicon Nanowires

    Science.gov (United States)

    Qu, Yongquan; Zhou, Hailong; Duan, Xiangfeng

    2011-01-01

    In this minreview, we summarize recent progress in the synthesis, properties and applications of a new type of one-dimensional nanostructures — single crystalline porous silicon nanowires. The growth of porous silicon nanowires starting from both p- and n-type Si wafers with a variety of dopant concentrations can be achieved through either one-step or two-step reactions. The mechanistic studies indicate the dopant concentration of Si wafers, oxidizer concentration, etching time and temperature can affect the morphology of the as-etched silicon nanowires. The porous silicon nanowires are both optically and electronically active and have been explored for potential applications in diverse areas including photocatalysis, lithium ion battery, gas sensor and drug delivery. PMID:21869999

  10. Nanostructured silicon for thermoelectric

    Science.gov (United States)

    Stranz, A.; Kähler, J.; Waag, A.; Peiner, E.

    2011-06-01

    Thermoelectric modules convert thermal energy into electrical energy and vice versa. At present bismuth telluride is the most widely commercial used material for thermoelectric energy conversion. There are many applications where bismuth telluride modules are installed, mainly for refrigeration. However, bismuth telluride as material for energy generation in large scale has some disadvantages. Its availability is limited, it is hot stable at higher temperatures (>250°C) and manufacturing cost is relatively high. An alternative material for energy conversion in the future could be silicon. The technological processing of silicon is well advanced due to the rapid development of microelectronics in recent years. Silicon is largely available and environmentally friendly. The operating temperature of silicon thermoelectric generators can be much higher than of bismuth telluride. Today silicon is rarely used as a thermoelectric material because of its high thermal conductivity. In order to use silicon as an efficient thermoelectric material, it is necessary to reduce its thermal conductivity, while maintaining high electrical conductivity and high Seebeck coefficient. This can be done by nanostructuring into arrays of pillars. Fabrication of silicon pillars using ICP-cryogenic dry etching (Inductive Coupled Plasma) will be described. Their uniform height of the pillars allows simultaneous connecting of all pillars of an array. The pillars have diameters down to 180 nm and their height was selected between 1 micron and 10 microns. Measurement of electrical resistance of single silicon pillars will be presented which is done in a scanning electron microscope (SEM) equipped with nanomanipulators. Furthermore, measurement of thermal conductivity of single pillars with different diameters using the 3ω method will be shown.

  11. Study on Silicon detectors

    International Nuclear Information System (INIS)

    Gervino, G.; Boero, M.; Manfredotti, C.; Icardi, M.; Gabutti, A.; Bagnolatti, E.; Monticone, E.

    1990-01-01

    Prototypes of Silicon microstrip detectors and Silicon large area detectors (3x2 cm 2 ), realized directly by our group, either by ion implantation or by diffusion are presented. The physical detector characteristics and their performances determined by exposing them to different radioactive sources and the results of extensive tests on passivation, where new technological ways have been investigated, are discussed. The calculation of the different terms contributing to the total dark current is reported

  12. Subwavelength silicon photonics

    International Nuclear Information System (INIS)

    Cheben, P.; Bock, P.J.; Schmid, J.H.; Lapointe, J.; Janz, S.; Xu, D.-X.; Densmore, A.; Delage, A.; Lamontagne, B.; Florjanczyk, M.; Ma, R.

    2011-01-01

    With the goal of developing photonic components that are compatible with silicon microelectronic integrated circuits, silicon photonics has been the subject of intense research activity. Silicon is an excellent material for confining and manipulating light at the submicrometer scale. Silicon optoelectronic integrated devices have the potential to be miniaturized and mass-produced at affordable cost for many applications, including telecommunications, optical interconnects, medical screening, and biological and chemical sensing. We review recent advances in silicon photonics research at the National Research Council Canada. A new type of optical waveguide is presented, exploiting subwavelength grating (SWG) effect. We demonstrate subwavelength grating waveguides made of silicon, including practical components operating at telecom wavelengths: input couplers, waveguide crossings and spectrometer chips. SWG technique avoids loss and wavelength resonances due to diffraction effects and allows for single-mode operation with direct control of the mode confinement by changing the refractive index of a waveguide core over a range as broad as 1.6 - 3.5 simply by lithographic patterning. The light can be launched to these waveguides with a coupling loss as small as 0.5 dB and with minimal wavelength dependence, using coupling structures similar to that shown in Fig. 1. The subwavelength grating waveguides can cross each other with minimal loss and negligible crosstalk which allows massive photonic circuit connectivity to overcome the limits of electrical interconnects. These results suggest that the SWG waveguides could become key elements for future integrated photonic circuits. (authors)

  13. Silicon microphotonic waveguides

    International Nuclear Information System (INIS)

    Ta'eed, V.; Steel, M.J.; Grillet, C.; Eggleton, B.; Du, J.; Glasscock, J.; Savvides, N.

    2004-01-01

    Full text: Silicon microphotonic devices have been drawing increasing attention in the past few years. The high index-difference between silicon and its oxide (Δn = 2) suggests a potential for high-density integration of optical functions on to a photonic chip. Additionally, it has been shown that silicon exhibits strong Raman nonlinearity, a necessary property as light interaction can occur only by means of nonlinearities in the propagation medium. The small dimensions of silicon waveguides require the design of efficient tapers to couple light to them. We have used the beam propagation method (RSoft BeamPROP) to understand the principles and design of an inverse-taper mode-converter as implemented in several recent papers. We report on progress in the design and fabrication of silicon-based waveguides. Preliminary work has been conducted by patterning silicon-on-insulator (SOI) wafers using optical lithography and reactive ion etching. Thus far, only rib waveguides have been designed, as single-mode ridge-waveguides are beyond the capabilities of conventional optical lithography. We have recently moved to electron beam lithography as the higher resolutions permitted will provide the flexibility to begin fabricating sub-micron waveguides

  14. Asymmetric Supercapacitors Using 3D Nanoporous Carbon and Cobalt Oxide Electrodes Synthesized from a Single Metal-Organic Framework.

    Science.gov (United States)

    Salunkhe, Rahul R; Tang, Jing; Kamachi, Yuichiro; Nakato, Teruyuki; Kim, Jung Ho; Yamauchi, Yusuke

    2015-06-23

    Nanoporous carbon and nanoporous cobalt oxide (Co3O4) materials have been selectively prepared from a single metal-organic framework (MOF) (zeolitic imidazolate framework, ZIF-67) by optimizing the annealing conditions. The resulting ZIF-derived carbon possesses highly graphitic walls and a high specific surface area of 350 m(2)·g(-1), while the resulting ZIF-derived nanoporous Co3O4 possesses a high specific surface area of 148 m(2)·g(-1) with much less carbon content (1.7 at%). When nanoporous carbon and nanoporous Co3O4 were tested as electrode materials for supercapacitor application, they showed high capacitance values (272 and 504 F·g(-1), respectively, at a scan rate of 5 mV·s(-1)). To further demonstrate the advantages of our ZIF-derived nanoporous materials, symmetric (SSCs) and asymmetric supercapacitors (ASCs) were also fabricated using nanoporous carbon and nanoporous Co3O4 electrodes. Improved capacitance performance was successfully realized for the ASC (Co3O4//carbon), better than those of the SSCs based on nanoporous carbon and nanoporous Co3O4 materials (i.e., carbon//carbon and Co3O4//Co3O4). The developed ASC with an optimal mass loading can be operated within a wide potential window of 0.0-1.6 V, which leads to a high specific energy of 36 W·h·kg(-1). More interestingly, this ASC also exhibits excellent rate capability (with the highest specific power of 8000 W·kg(-1) at a specific energy of 15 W·h·kg(-1)) combined with long-term stability up to 2000 cycles.

  15. Amorphous silicon crystalline silicon heterojunction solar cells

    CERN Document Server

    Fahrner, Wolfgang Rainer

    2013-01-01

    Amorphous Silicon/Crystalline Silicon Solar Cells deals with some typical properties of heterojunction solar cells, such as their history, the properties and the challenges of the cells, some important measurement tools, some simulation programs and a brief survey of the state of the art, aiming to provide an initial framework in this field and serve as a ready reference for all those interested in the subject. This book helps to "fill in the blanks" on heterojunction solar cells. Readers will receive a comprehensive overview of the principles, structures, processing techniques and the current developmental states of the devices. Prof. Dr. Wolfgang R. Fahrner is a professor at the University of Hagen, Germany and Nanchang University, China.

  16. Oxygen defect processes in silicon and silicon germanium

    KAUST Repository

    Chroneos, A.; Sgourou, E. N.; Londos, C. A.; Schwingenschlö gl, Udo

    2015-01-01

    Silicon and silicon germanium are the archetypical elemental and alloy semiconductor materials for nanoelectronic, sensor, and photovoltaic applications. The investigation of radiation induced defects involving oxygen, carbon, and intrinsic defects is important for the improvement of devices as these defects can have a deleterious impact on the properties of silicon and silicon germanium. In the present review, we mainly focus on oxygen-related defects and the impact of isovalent doping on their properties in silicon and silicon germanium. The efficacy of the isovalent doping strategies to constrain the oxygen-related defects is discussed in view of recent infrared spectroscopy and density functional theory studies.

  17. Colloidal characterization of ultrafine silicon carbide and silicon nitride powders

    Science.gov (United States)

    Whitman, Pamela K.; Feke, Donald L.

    1986-01-01

    The effects of various powder treatment strategies on the colloid chemistry of aqueous dispersions of silicon carbide and silicon nitride are examined using a surface titration methodology. Pretreatments are used to differentiate between the true surface chemistry of the powders and artifacts resulting from exposure history. Silicon nitride powders require more extensive pretreatment to reveal consistent surface chemistry than do silicon carbide powders. As measured by titration, the degree of proton adsorption from the suspending fluid by pretreated silicon nitride and silicon carbide powders can both be made similar to that of silica.

  18. Oxygen defect processes in silicon and silicon germanium

    KAUST Repository

    Chroneos, A.

    2015-06-18

    Silicon and silicon germanium are the archetypical elemental and alloy semiconductor materials for nanoelectronic, sensor, and photovoltaic applications. The investigation of radiation induced defects involving oxygen, carbon, and intrinsic defects is important for the improvement of devices as these defects can have a deleterious impact on the properties of silicon and silicon germanium. In the present review, we mainly focus on oxygen-related defects and the impact of isovalent doping on their properties in silicon and silicon germanium. The efficacy of the isovalent doping strategies to constrain the oxygen-related defects is discussed in view of recent infrared spectroscopy and density functional theory studies.

  19. Polyhedral Boranes: A Versatile Building Block for Nanoporous Materials

    Science.gov (United States)

    Clingerman, Daniel Jon

    The studies described in this dissertation examine several new concepts related to polyhedral boranes and their applications towards the synthesis of novel nanoporous materials. The unique thermal and chemical robustness, rigidity, quasi-spherical geometry, and high boron content of polyhedral boranes are explored to generate materials not possible with typical organic synthons. Aside from the fundamental synthetic work, this work was also aimed at solving larger global issues such as energy storage and new routes to therapeutics. Chapter 2 highlights the discovery of the first highly porous carborane-based metal-organic framework, where the spherical nature of the carborane increases volumetric surface area without reducing pore volume. Chapter 3 examines the first tritopic carborane-based ligand and the stabilizing effect the rigid, sterically bulky carboranyl groups have on highly porous topologies not stable with typical organic ligands. Chapters 4 and 5 describe the use of polyhedral borane-based ligands as a means to influence and generate unexpected topologies. Lastly, chapter 6 explores using a simple carborane-based ligand that harnesses the power of coordination-driven assembly to rapidly generate a high boron-containing supramolecular cuboctahedron.

  20. Theoretical investigation of gas separation in functionalized nanoporous graphene membranes

    Science.gov (United States)

    Wang, Yong; Yang, Qingyuan; Zhong, Chongli; Li, Jinping

    2017-06-01

    Graphene has enormous potential as a membrane-separation material with ultrahigh permeability and selectivity. The understanding of mass-transport mechanism in graphene membranes is crucial for applications in gas separation field. We computationally investigated the capability and mechanisms of functionalized nanoporous graphene membranes for gas separation. The functionalized graphene membranes with appropriate pore size and geometry possess excellent high selectivity for separating CO2/N2, CO2/CH4 and N2/CH4 gas mixtures with a gas permeance of ∼103-105 GPU, compared with ∼100 GPU for typical polymeric membranes. More important, we found that, for ultrathin graphene membranes, the gas separation performance has a great dependence not only with the energy barrier for gas getting into the pore of the graphene membranes, but also with the energy barrier for gas escaping from the pore to the other side of the membranes. The gas separation performance can be tuned by changing the two energy barriers, which can be realized by varying the chemical functional groups on the pore rim of the graphene. The novel mass-transport mechanism obtained in current study may provide a theoretical foundation for guiding the future design of graphene membranes with outstanding separation performance.

  1. Polymer translocation through a nanopore: a showcase of anomalous diffusion.

    Science.gov (United States)

    Milchev, A; Dubbeldam, Johan L A; Rostiashvili, Vakhtang G; Vilgis, Thomas A

    2009-04-01

    We investigate the translocation dynamics of a polymer chain threaded through a membrane nanopore by a chemical potential gradient that acts on the chain segments inside the pore. By means of diverse methods (scaling theory, fractional calculus, and Monte Carlo and molecular dynamics simulations), we demonstrate that the relevant dynamic variable, the transported number of polymer segments, s(t), displays an anomalous diffusive behavior, both with and without an external driving force being present. We show that in the absence of drag force the time tau, needed for a macromolecule of length N to thread from the cis into the trans side of a cell membrane, scales as tauN(2/alpha) with the chain length. The anomalous dynamics of the translocation process is governed by a universal exponent alpha= 2/(2nu + 2 - gamma(1)), which contains the basic universal exponents of polymer physics, nu (the Flory exponent) and gamma(1) (the surface entropic exponent). A closed analytic expression for the probability to find s translocated segments at time t in terms of chain length N and applied drag force f is derived from the fractional Fokker-Planck equation, and shown to provide analytic results for the time variation of the statistical moments and . It turns out that the average translocation time scales as tau proportional, f(-1)N(2/alpha-1). These results are tested and found to be in perfect agreement with extensive Monte Carlo and molecular dynamics computer simulations.

  2. Conformational Thermodynamics of DNA Strands in Hydrophilic Nanopores.

    Science.gov (United States)

    Cruz, Fernando J A L; Mota, Jose P B

    2016-08-18

    Enhanced sampling techniques spanning a sub-microsecond timescale reveal that a double-stranded DNA dodecamer can be spontaneously encapsulated into (51,0) and (40,0) single-walled carbon nanotubes under the influence of an electric field, leading to hybrids with a 40 kJ/mol enhanced free-energy. The confinement mechanism allows the nucleic acid to retain its mobility, diffusing anisotropically along the endohedral volume, visiting regions of space determined by entropic factors (diameter, free-volume) and linked by a thermodynamical highway. In spite of the energetic similarities between both topologies (4.1× 103 kJ/mol), the biomolecule favours positioning either parallel to the nanopore central axis, (40,0), or in close contact with the solid walls, (51,0), in the latter encasing a hollow cylindrical domain of diameter 1 - 1.5 nm. Precise physiological conditions allow the extrapolation of results to in vivo systems and constitute a novel and thorough contribution to nanotube technology in the areas of nucleic acid encapsulation/delivery and personalized therapeutics.

  3. Forced Translocation of Polymer through Nanopore: Deterministic Model and Simulations

    Science.gov (United States)

    Wang, Yanqian; Panyukov, Sergey; Liao, Qi; Rubinstein, Michael

    2012-02-01

    We propose a new theoretical model of forced translocation of a polymer chain through a nanopore. We assume that DNA translocation at high fields proceeds too fast for the chain to relax, and thus the chain unravels loop by loop in an almost deterministic way. So the distribution of translocation times of a given monomer is controlled by the initial conformation of the chain (the distribution of its loops). Our model predicts the translocation time of each monomer as an explicit function of initial polymer conformation. We refer to this concept as ``fingerprinting''. The width of the translocation time distribution is determined by the loop distribution in initial conformation as well as by the thermal fluctuations of the polymer chain during the translocation process. We show that the conformational broadening δt of translocation times of m-th monomer δtm^1.5 is stronger than the thermal broadening δtm^1.25 The predictions of our deterministic model were verified by extensive molecular dynamics simulations

  4. Magnetic properties of ferromagnetic nanowires embedded in nanoporous alumina membranes

    International Nuclear Information System (INIS)

    Kroell, M.; Blau, W.J.; Grandjean, D.; Benfield, R.E.; Luis, F.; Paulus, P.M.; Jongh, L.J. de

    2002-01-01

    Iron, nickel and cobalt nanowires are prepared within the pores of nanoporous alumina membranes using an electrochemical AC plating procedure. Nanowires produced in this way can be easily varied in diameter (5-250 nm) and length (up to several hundred microns). The magnetisation curves for these nanowire/alumina composites can then be determined not only as a function of the temperature but also as a function of the wire diameter and length. Conclusions regarding the magnetisation reversal processes that take place in the wires can be drawn. For Fe and Ni nanowires, we show that the magnetisation process in wires with a diameter smaller than the domain wall width is independent of the wire length and probably takes place via the formation of a small magnetic domain at the end of the wires and a subsequent propagation of the domain wall along the wire. For Co nanowires a competition between the shape anisotropy and the temperature- and size-dependent magnetocrystalline anisotropy could be observed

  5. Tunable Impedance Spectroscopy Sensors via Selective Nanoporous Materials.

    Energy Technology Data Exchange (ETDEWEB)

    Nenoff, Tina M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Small, Leo J [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-09-01

    Impedance spectroscopy was leveraged to directly detect the sorption of I 2 by selective adsorption into nanoporous metal organic frameworks (MOF). Films of three different types of MOF frameworks, respectively, were drop cast onto platinum interdigitated electrodes, dried, and exposed to gaseous I 2 at 25, 40, or 70 C. The MOF frameworks varied in topology from small pores (equivalent to I 2 diameter) to large pore frameworks. The combination of the chemistry of the framework and pore size dictated quantity and kinetics of I 2 adsorption. Air, argon, methanol, and water were found to produce minimal changes in ZIF-8 impedance. Independent of MOF framework characteristics, all resultant sensors showed high response to I 2 in air. As an example of sensor output, I 2 was readily detected at 25 C in air within 720 s of exposure, using an un-optimized sensor geometry with a small pored MOF. Further optimization of sensor geometry, decreasing MOF film thicknesses and maximizing sensor capacitance, will enable faster detection of trace I 2 .

  6. Biofouling-resilient nanoporous gold electrodes for DNA sensing.

    Science.gov (United States)

    Daggumati, Pallavi; Matharu, Zimple; Wang, Ling; Seker, Erkin

    2015-09-01

    Electrochemical nucleic acid sensors are promising tools for point-of-care diagnostic platforms with their facile integration with electronics and scalability. However, nucleic acid detection in complex biological fluids is challenging as biomolecules nonspecifically adsorb on the electrode surface and adversely affect the sensor performance by obscuring the transport of analytes and redox species to the electrode. We report that nanoporous gold (np-Au) electrodes, prepared by a microfabrication-compatible self-assembly process and functionalized with DNA probes, enabled detection of target DNA molecules (10-200 nM) in physiologically relevant complex media (bovine serum albumin and fetal bovine serum). In contrast, the sensor performance was compromised for planar gold electrodes in the same conditions. Hybridization efficiency decreased by 10% for np-Au with coarser pores revealing a pore-size dependence of sensor performance in biofouling conditions. This nanostructure-dependent functionality in complex media suggests that the pores with the optimal size and geometry act as sieves for blocking the biomolecules from inhibiting the surfaces within the porous volume while allowing the transport of nucleic acid analytes and redox molecules.

  7. DEVELOPMENT OF DOPED NANOPOROUS CARBONS FOR HYDROGEN STORAGE

    Energy Technology Data Exchange (ETDEWEB)

    Lueking, Angela D.; Li, Qixiu; Badding, John V.; Fonseca, Dania; Gutierrez, Humerto; Sakti, Apurba; Adu, Kofi; Schimmel, Michael

    2010-03-31

    Hydrogen storage materials based on the hydrogen spillover mechanism onto metal-doped nanoporous carbons are studied, in an effort to develop materials that store appreciable hydrogen at ambient temperatures and moderate pressures. We demonstrate that oxidation of the carbon surface can significantly increase the hydrogen uptake of these materials, primarily at low pressure. Trace water present in the system plays a role in the development of active sites, and may further be used as a strategy to increase uptake. Increased surface density of oxygen groups led to a significant enhancement of hydrogen spillover at pressures less than 100 milibar. At 300K, the hydrogen uptake was up to 1.1 wt. % at 100 mbar and increased to 1.4 wt. % at 20 bar. However, only 0.4 wt% of this was desorbable via a pressure reduction at room temperature, and the high lowpressure hydrogen uptake was found only when trace water was present during pretreatment. Although far from DOE hydrogen storage targets, storage at ambient temperature has significant practical advantages oner cryogenic physical adsorbents. The role of trace water in surface modification has significant implications for reproducibility in the field. High-pressure in situ characterization of ideal carbon surfaces in hydrogen suggests re-hybridization is not likely under conditions of practical interest. Advanced characterization is used to probe carbon-hydrogen-metal interactions in a number of systems and new carbon materials have been developed.

  8. Confinement effects and mechanistic aspects for montmorillonite nanopores.

    Science.gov (United States)

    Li, Xiong; Zhu, Chang; Jia, Zengqiang; Yang, Gang

    2018-08-01

    Owing to the ubiquity, critical importance and special properties, confined microenvironments have recently triggered overwhelming interest. In this work, all-atom molecular dynamics simulations have been conducted to address the confinement effects and ion-specific effects for electrolyte solutions within montmorillonite nanopores, where the pore widths vary with a wide range. The adsorption number, structure, dynamics and stability of inner- and outer-sphere metal ions are affected by the change of pore widths (confinement effects), while the extents are significantly dependent on the type of adsorbed species. The type of adsorbed species is, however, not altered by the magnitude of confinement effects, and confinement effects are similar for different electrolyte concentrations. Ion-specific effects are pronounced for all magnitudes of confinement effects (from non- to strong confined conditions), and Hofmeister sequences of outer-sphere species are closely associated with the magnitude of confinement effects while those of inner-sphere species remain consistent. In addition, mechanistic aspects of confinement have been posed using the electrical double layer theories, and the results can be generalized to other confined systems that are ubiquitous in biology, chemistry, geology and nanotechnology. Copyright © 2018 Elsevier Inc. All rights reserved.

  9. Stable lithium electrodeposition in liquid and nanoporous solid electrolytes

    KAUST Repository

    Lu, Yingying

    2014-08-10

    Rechargeable lithium, sodium and aluminium metal-based batteries are among the most versatile platforms for high-energy, cost-effective electrochemical energy storage. Non-uniform metal deposition and dendrite formation on the negative electrode during repeated cycles of charge and discharge are major hurdles to commercialization of energy-storage devices based on each of these chemistries. A long-held view is that unstable electrodeposition is a consequence of inherent characteristics of these metals and their inability to form uniform electrodeposits on surfaces with inevitable defects. We report on electrodeposition of lithium in simple liquid electrolytes and in nanoporous solids infused with liquid electrolytes. We find that simple liquid electrolytes reinforced with halogenated salt blends exhibit stable long-term cycling at room temperature, often with no signs of deposition instabilities over hundreds of cycles of charge and discharge and thousands of operating hours. We rationalize these observations with the help of surface energy data for the electrolyte/lithium interface and impedance analysis of the interface during different stages of cell operation. Our findings provide support for an important recent theoretical prediction that the surface mobility of lithium is significantly enhanced in the presence of lithium halide salts. Our results also show that a high electrolyte modulus is unnecessary for stable electrodeposition of lithium.

  10. Nanoporous Calcium Silicate and PLGA Bio composite for Bone Repair

    International Nuclear Information System (INIS)

    Su, J.; Wang, Z.; Wu, Y.; Cao, L.; Ma, Y.; Yu, B.; Li, M.; Yan, Y.

    2010-01-01

    Nanoporous calcium silicate (n-CS) with high surface area was synthesized using the mixed surfactants of EO20PO70EO20 (polyethylene oxide)20(polypropylene oxide)70(polyethylene oxide)20, P123) and hexadecyltrimethyl ammonium bromide (CTAB) as templates, and its composite with poly(lactic acid-co-glycolic acid) (PLGA) were fabricated. The results showed that the n-CS/PLGA composite (n-CPC) with 20 wt% n-CS could induce a dense and continuous layer of apatite on its surface after soaking in simulated body fluid (SBF) for 1 week, suggesting the excellent in vitro bioactivity. The n-CPC could promote cell attachment on its surfaces. In addition, the proliferation ratio of MG63 cells on n-CPC was significantly higher than PLGA; the results demonstrated that n-CPC had excellent cytocompatibility. We prepared n-CPC scaffolds that contained open and interconnected macroporous ranging in size from 200 to 500 μ m. The n-CPC scaffolds were implanted in femur bone defect of rabbits, and the in vivo biocompatibility and osteogenicity of the scaffolds were investigated. The results indicated that n-CPC scaffolds exhibited good biocompatibility, degradability, and osteogenesis in vivo. Collectively, these results suggested that the incorporation of n-CS in PLGA produced biocomposites with improved bioactivity and biocompatibility.

  11. Detecting a single molecule using a micropore-nanopore hybrid chip.

    Science.gov (United States)

    Liu, Lei; Zhu, Lizhong; Ni, Zhonghua; Chen, Yunfei

    2013-11-21

    Nanopore-based DNA sequencing and biomolecule sensing have attracted more and more attention. In this work, novel sensing devices were built on the basis of the chips containing nanopore arrays in polycarbonate (PC) membranes and micropores in Si3N4 films. Using the integrated chips, the transmembrane ionic current induced by biomolecule's translocation was recorded and analyzed, which suggested that the detected current did not change linearly as commonly expected with increasing biomolecule concentration. On the other hand, detailed translocation information (such as translocation gesture) was also extracted from the discrete current blockages in basic current curves. These results indicated that the nanofluidic device based on the chips integrated by micropores and nanopores possessed comparative potentials in biomolecule sensing.

  12. Hydrothermally formed three-dimensional nanoporous Ni(OH)2 thin-film supercapacitors.

    Science.gov (United States)

    Yang, Yang; Li, Lei; Ruan, Gedeng; Fei, Huilong; Xiang, Changsheng; Fan, Xiujun; Tour, James M

    2014-09-23

    A three-dimensional nanoporous Ni(OH)2 thin-film was hydrothermally converted from an anodically formed porous layer of nickel fluoride/oxide. The nanoporous Ni(OH)2 thin-films can be used as additive-free electrodes for energy storage. The nanoporous layer delivers a high capacitance of 1765 F g(-1) under three electrode testing. After assembly with porous activated carbon in asymmetric supercapacitor configurations, the devices deliver superior supercapacitive performances with capacitance of 192 F g(-1), energy density of 68 Wh kg(-1), and power density of 44 kW kg(-1). The wide working potential window (up to 1.6 V in 6 M aq KOH) and stable cyclability (∼90% capacitance retention over 10,000 cycles) make the thin-film ideal for practical supercapacitor devices.

  13. Nanoporous Polymer Films of Cyanate Ester Resins Designed by Using Ionic Liquids as Porogens.

    Science.gov (United States)

    Fainleib, Alexander; Vashchuk, Alina; Starostenko, Olga; Grigoryeva, Olga; Rogalsky, Sergiy; Nguyen, Thi-Thanh-Tam; Grande, Daniel

    2017-12-01

    Novel nanoporous film materials of thermostable cyanate ester resins (CERs) were generated by polycyclotrimerization of dicyanate ester of bisphenol E in the presence of varying amounts (from 20 to 40 wt%) of an ionic liquid (IL), i.e., 1-heptylpyridinium tetrafluoroborate, followed by its quantitative extraction after complete CER network formation. The completion of CER formation and IL extraction was assessed using gel fraction content determination, FTIR, 1 H NMR, and energy-dispersive X-ray spectroscopy (EDX). SEM and DSC-based thermoporometry analyses demonstrated the formation of nanoporous structures after IL removal from CER networks, thus showing the effective role of IL as a porogen. Pore sizes varied from ~20 to ~180 nm with an average pore diameter of around 45-60 nm depending on the initial IL content. The thermal stability of nanoporous CER-based films was investigated by thermogravimetric analysis.

  14. Wettability modified nanoporous ceramic membrane for simultaneous residual heat and condensate recovery

    Science.gov (United States)

    Hu, H. W.; Tang, G. H.; Niu, D.

    2016-06-01

    Recovery of both latent heat and condensate from boiler flue gas is significant for improving boiler efficiency and water conservation. The condensation experiments are carried out to investigate the simultaneous heat and mass transfer across the nanoporous ceramic membranes (NPCMs) which are treated to be hydrophilic and hydrophobic surfaces using the semicontinuous supercritical reactions. The effects of typical parameters including coolant flow rate, vapor/nitrogen gas mixture temperature, water vapor volume fraction and transmembrane pressure on heat and mass transfer performance are studied. The experimental results show that the hydrophilic NPCM exhibits higher performances of condensation heat transfer and condensate recovery. However, the hydrophobic modification results in remarkable degradation of heat and condensate recovery from the mixture. Molecular dynamics simulations are conducted to establish a hydrophilic/hydrophobic nanopore/water liquid system, and the infiltration characteristics of the single hydrophilic/hydrophobic nanopore is revealed.

  15. Wettability modified nanoporous ceramic membrane for simultaneous residual heat and condensate recovery.

    Science.gov (United States)

    Hu, H W; Tang, G H; Niu, D

    2016-06-07

    Recovery of both latent heat and condensate from boiler flue gas is significant for improving boiler efficiency and water conservation. The condensation experiments are carried out to investigate the simultaneous heat and mass transfer across the nanoporous ceramic membranes (NPCMs) which are treated to be hydrophilic and hydrophobic surfaces using the semicontinuous supercritical reactions. The effects of typical parameters including coolant flow rate, vapor/nitrogen gas mixture temperature, water vapor volume fraction and transmembrane pressure on heat and mass transfer performance are studied. The experimental results show that the hydrophilic NPCM exhibits higher performances of condensation heat transfer and condensate recovery. However, the hydrophobic modification results in remarkable degradation of heat and condensate recovery from the mixture. Molecular dynamics simulations are conducted to establish a hydrophilic/hydrophobic nanopore/water liquid system, and the infiltration characteristics of the single hydrophilic/hydrophobic nanopore is revealed.

  16. Enhancing the platinum atomic layer deposition infiltration depth inside anodic alumina nanoporous membrane

    Energy Technology Data Exchange (ETDEWEB)

    Vaish, Amit, E-mail: anv@udel.edu; Krueger, Susan; Dimitriou, Michael; Majkrzak, Charles [National Institute of Standards and Technology (NIST) Center for Neutron Research, Gaithersburg, MD 20899-8313 (United States); Vanderah, David J. [Institute for Bioscience and Biotechnology Research, NIST, Rockville, Maryland 20850 (United States); Chen, Lei, E-mail: lei.chen@nist.gov [NIST Center for Nanoscale Science and Technology, Gaithersburg, Maryland 20899-8313 (United States); Gawrisch, Klaus [Laboratory of Membrane Biochemistry and Biophysics, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland 20892 (United States)

    2015-01-15

    Nanoporous platinum membranes can be straightforwardly fabricated by forming a Pt coating inside the nanopores of anodic alumina membranes (AAO) using atomic layer deposition (ALD). However, the high-aspect-ratio of AAO makes Pt ALD very challenging. By tuning the process deposition temperature and precursor exposure time, enhanced infiltration depth along with conformal coating was achieved for Pt ALD inside the AAO templates. Cross-sectional scanning electron microscopy/energy dispersive x-ray spectroscopy and small angle neutron scattering were employed to analyze the Pt coverage and thickness inside the AAO nanopores. Additionally, one application of platinum-coated membrane was demonstrated by creating a high-density protein-functionalized interface.

  17. High-temperature nanoporous ceramic monolith prepared from a polymeric bicontinuous microemulsion template.

    Science.gov (United States)

    Jones, Brad H; Lodge, Timothy P

    2009-02-11

    Nanoporous ceramic with a unique pore structure was derived from an all-hydrocarbon polymeric bicontinuous microemulsion (BmuE). The BmuE was designed to allow facile removal of one phase, resulting in a nanoporous polymer monolith with BmuE-like structure. The pores were filled with a commercially available, polymeric precursor to nonoxide, Si-based ceramics. Pyrolysis resulted in a monolith of nanoporous ceramic, stable to at least 1000 degrees C, with a BmuE-like pore structure. The pore structure is disordered and 3-D continuous. Microscopy and gas sorption measurements suggest a well-defined pore size distribution spanning roughly 60-100 nm, sizes previously unattainable through related techniques.

  18. Effect of Nanopore Length on the Translocation Process of a Biopolymer: Numerical Study

    Directory of Open Access Journals (Sweden)

    Yong Kweon Suh

    2013-09-01

    Full Text Available In this study, we simulate the electrophoretic motion of a bio-polymer through a synthetic nanopore in the presence of an external bias voltage by considering the hydrodynamic interactions between the polymer and the fluid explicitly. The motion of the polymer is simulated by 3D Langevin dynamics technique by modeling the polymer as a worm-like-chain, while the hydrodynamic interactions are incorporated by the lattice Boltzmann equation. We report the simulation results for three different lengths of the nanopore. The translocation time increases with the pore length even though the electrophoretic force on the polymer is the same irrespective of the pore length. This is attributed to the fact that the translocation velocity of each bead inside the nanopore decreases with the pore length due to the increased fluid resistance force caused by the increase in the straightened portion of the polymer. We confirmed this using a theoretical formula.

  19. Nanoporous niobium nitride (Nb2N) with enhanced electrocatalytic performance for hydrogen evolution

    Science.gov (United States)

    Li, Yan; Zhang, Jianli; Qian, Xingyue; Zhang, Yue; Wang, Yining; Hu, Rudan; Yao, Chao; Zhu, Junwu

    2018-01-01

    The transition metal nitrides (TMNs) with nanoporous structure have shown great promise as potential electrocatalysts for the hydrogen evolution reaction (HER). Herein, self-organized nanoporous Nb2N was first successfully synthesized through the anodization of niobium in mixed oxalic acid/HF electrolyte, followed by a simple annealing treatment in the ammonia atmosphere. Due to the highly ordered nanoporous structure with abundant active sites and the enhanced electrical conductivity, the Nb2N exhibits a high catalytic current (326.3 mA cm-2) and low onset potential (96.3 mV), which is almost 3.9 times and 4.2 times better than that of Nb2O5, respectively. Meanwhile, the Nb2N also presents low Tafel slope (92 mV dec-1), and excellent cycling durability. More importantly, this study will provide more opportunities for designing and fabricating niobium compounds as an innovative HER catalysts.

  20. Origin of the electrophoretic force on DNA in solid-state nanopores

    Science.gov (United States)

    van Dorp, Stijn; Keyser, Ulrich F.; Dekker, Nynke H.; Dekker, Cees; Lemay, Serge G.

    2009-05-01

    Despite gel electrophoresis being one of the main workhorses of molecular biology, the physics of polyelectrolyte electrophoresis in a strongly confined environment remains poorly understood. Theory indicates that forces in electrophoresis result from interplay between ionic screening and hydrodynamics, but these ideas could so far be addressed only indirectly by experiments based on macroscopic porous gels. Here, we provide a first direct experimental test by measuring the electrophoretic force on a single DNA molecule threading through a solid-state nanopore as a function of pore size. The stall force gradually decreases on increasing the nanopore diameter from 6 to 90nm, inconsistent with expectations from simple electrostatics and strikingly demonstrating the influence of the hydrodynamic environment. We model this process by applying the coupled Poisson-Boltzmann and Stokes equations in the nanopore geometry and find good agreement with the experimental results.

  1. Synthesis of self-detached nanoporous titanium-based metal oxide

    International Nuclear Information System (INIS)

    Hu, F.; Wen, Y.; Chan, K.C.; Yue, T.M.; Zhou, Y.Z.; Zhu, S.L.; Yang, X.J.

    2015-01-01

    In this study, self-detached nanoporous titanium-based metal oxide was synthesized for the first time by ultrafast anodization in a fluoride-free electrolyte containing 10% HNO 3 . The nanoporous oxide has through-holes with diameters ranging from 10 to 60 nm. The as-formed oxides are amorphous, and were transformed to crystalline structures by annealing. The performance of a dye sensitized solar cell using nanoporpous Ti–10Zr oxide (TZ10) was further studied. It was found that the TZ10 film could increase both the short-circuit current and the open-circuit photovoltage of the solar cell. The overall efficiency of the solar cell was 6.99%, an increase of 20.7% as compared to that using a pure TiO 2 (P25) film. - Graphical abstract: The nanoporous Ti–xZr(x=10, 30) oxide layers are fabricated by anodizing in a dilute nitric acid solvent. The power conversion efficiency of the DSSC by a covering of a Ti–10Zr thin film is increased by 20.7%, with an η of 7.69% , a short circuit current of 12.4 mA/cm 2 , a open circuit voltage of 0.833 V, and a fill factor of 0.679. - Highlights: • Self-detached nanoporous titanium-based metal (TiZr) oxide was synthesized. • The TiZr oxides have through-hole nanopores with diameters ranging from 10 to 60 nm. • The nanoporous Ti–10Zr oxide can improve the power conversion efficiency of a DSSC

  2. Nanoporous gold microelectrode prepared from potential modulated electrochemical alloying–dealloying in ionic liquid

    International Nuclear Information System (INIS)

    Jiang, Junhua; Wang, Xinying; Zhang, Lei

    2013-01-01

    Highlights: • A green chemistry method for producing nanoporous gold microelectrode was studied. • An ionic liquid plating bath was utilized for electrochemical alloying–dealloying. • Nanostructures of gold surface layers can be tuned by modulating potential. • Nanoporous gold microelectrode has high surface area and merit of a microelectrode. • Nitrite oxidation and reduction on nanoporous gold microelectrode were studied. -- Abstract: Nanoporous gold (NPG) microelectrodes with high surface area and open pore network were successfully prepared by applying modulated potential to a polycrystalline Au-disk microelectrode in ionic liquid electrolyte containing ZnCl 2 at elevated temperature. During cathodic process, Zn is electrodeposited and interacted with Au microdisk substrate to form a AuZn alloy phase. During subsequent anodic process, Zn is selectively dissolved from the alloy phase, leading to the formation of a NPG layer which can grow with repetitive potential modulation. Scanning-electron microscope and energy dispersive X-ray microscope measurements show that the NPG microelectrodes possessing nanoporous structures can be tuned via potential modulation, and chemically contain a small amount of Zn whose presence has no obvious influence on electrochemical responses of the electrodes. Steady-state and cyclic voltammetric studies suggest that the NPG microelectrodes have high surface area and keep diffusional properties of a microelectrode. Electrochemical nitrite reduction and oxidation are studied as model reactions to demonstrate potential applications of the NPG microelectrodes in electrocatalysis and electroanalysis. These facts suggest that the potential-modulated electrochemical alloying/dealloying in ionic liquid electrolyte offers a convenient green-chemistry method for the preparation of nanoporous microelectrodes

  3. Synthesis of self-detached nanoporous titanium-based metal oxide

    Energy Technology Data Exchange (ETDEWEB)

    Hu, F. [Advanced Manufacturing Technology Research Center, Department of Industrial and Systems Engineering, The Hong Kong Polytechnic University (Hong Kong); Jiangxi Key Laboratory of Advanced Ceramic Materials, School of Materials Science and Engineering, Jingdezhen Ceramic Institute, Jiangxi 343001 (China); Wen, Y. [Jiangxi Key Laboratory of Advanced Ceramic Materials, School of Materials Science and Engineering, Jingdezhen Ceramic Institute, Jiangxi 343001 (China); Chan, K.C., E-mail: mfkcchan@inet.polyu.edu.hk [Advanced Manufacturing Technology Research Center, Department of Industrial and Systems Engineering, The Hong Kong Polytechnic University (Hong Kong); Yue, T.M. [Advanced Manufacturing Technology Research Center, Department of Industrial and Systems Engineering, The Hong Kong Polytechnic University (Hong Kong); Zhou, Y.Z. [Jiangxi Key Laboratory of Advanced Ceramic Materials, School of Materials Science and Engineering, Jingdezhen Ceramic Institute, Jiangxi 343001 (China); Zhu, S.L.; Yang, X.J. [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China)

    2015-09-15

    In this study, self-detached nanoporous titanium-based metal oxide was synthesized for the first time by ultrafast anodization in a fluoride-free electrolyte containing 10% HNO{sub 3}. The nanoporous oxide has through-holes with diameters ranging from 10 to 60 nm. The as-formed oxides are amorphous, and were transformed to crystalline structures by annealing. The performance of a dye sensitized solar cell using nanoporpous Ti–10Zr oxide (TZ10) was further studied. It was found that the TZ10 film could increase both the short-circuit current and the open-circuit photovoltage of the solar cell. The overall efficiency of the solar cell was 6.99%, an increase of 20.7% as compared to that using a pure TiO{sub 2} (P25) film. - Graphical abstract: The nanoporous Ti–xZr(x=10, 30) oxide layers are fabricated by anodizing in a dilute nitric acid solvent. The power conversion efficiency of the DSSC by a covering of a Ti–10Zr thin film is increased by 20.7%, with an η of 7.69% , a short circuit current of 12.4 mA/cm{sup 2}, a open circuit voltage of 0.833 V, and a fill factor of 0.679. - Highlights: • Self-detached nanoporous titanium-based metal (TiZr) oxide was synthesized. • The TiZr oxides have through-hole nanopores with diameters ranging from 10 to 60 nm. • The nanoporous Ti–10Zr oxide can improve the power conversion efficiency of a DSSC.

  4. Co-delivery of ibuprofen and gentamicin from nanoporous anodic titanium dioxide layers.

    Science.gov (United States)

    Pawlik, Anna; Jarosz, Magdalena; Syrek, Karolina; Sulka, Grzegorz D

    2017-04-01

    Although single-drug therapy may prove insufficient in treating bacterial infections or inflammation after orthopaedic surgeries, complex therapy (using both an antibiotic and an anti-inflammatory drug) is thought to address the problem. Among drug delivery systems (DDSs) with prolonged drug release profiles, nanoporous anodic titanium dioxide (ATO) layers on Ti foil are very promising. In the discussed research, ATO samples were synthesized via a three-step anodization process in an ethylene glycol-based electrolyte with fluoride ions. The third step lasted 2, 5 and 10min in order to obtain different thicknesses of nanoporous layers. Annealing the as-prepared amorphous layers at the temperature of 400°C led to obtaining the anatase phase. In this study, water-insoluble ibuprofen and water-soluble gentamicin were used as model drugs. Three different drug loading procedures were applied. The desorption-desorption-diffusion (DDD) model of the drug release was fitted to the experimental data. The effects of crystalline structure, depth of TiO 2 nanopores and loading procedure on the drug release profiles were examined. The duration of the drug release process can be easily altered by changing the drug loading sequence. Water-soluble gentamicin is released for a long period of time if gentamicin is loaded in ATO as the first drug. Additionally, deeper nanopores and anatase phase suppress the initial burst release of drugs. These results confirm that factors such as morphological and crystalline structure of ATO layers, and the procedure of drug loading inside nanopores, allow to alter the drug release performance of nanoporous ATO layers. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. FABRICATION OF NANOPOROUS Ni VIA DEALLOYING OF ZINC-NICKEL COATINGS

    OpenAIRE

    Seda , Oturak

    2015-01-01

    Dealloying is a selective leaching of one component in a multicomponent alloy so as to produce a nanoporous structure. In this study, it was aimed to produce nanoporous Ni coating by selective leaching of Zn in a Zn-Ni alloy. To achieve this, first the Zn-Ni alloy was obtained by electrodeposition in a bath containing Zn and Ni salts. Then, dealloying was performed at different concentrations of NaOH solution. Dealloying led to crack formation in the coatings which thus prevented the formatio...

  6. Non-aqueous nanoporous gold based supercapacitors with high specific energy

    International Nuclear Information System (INIS)

    Hou, Ying; Chen, Luyang; Hirata, Akihiko; Fujita, Takeshi; Chen, Mingwei

    2016-01-01

    In this study, we report that the supercapacitor performance of polypyrrole (PPy) in non-aqueous electrolytes can be dramatically improved by highly conductive nanoporous gold which acts as both the support of active PPy and the current collector of supercapacitors. The excellent electronic conductivity, rich porous structure and large surface area of the nanoporous electrodes give rise to a high specific capacitance and low internal resistance in non-aqueous electrolytes. Combining with a wide working potential window of ~ 2 V, the non-aqueous PPy-based supercapacitors show an extraordinary energy density and power density.

  7. Influences of Au ion radiation on microstructure and surface-enhanced Raman scattering of nanoporous copper

    Science.gov (United States)

    Wang, Jing; Hu, Zhaoyi; Li, Rui; Liu, Xiongjun; Xu, Chuan; Wang, Hui; Wu, Yuan; Fu, Engang; Lu, Zhaoping

    2018-05-01

    In this work, effects of Au ion irradiation on microstructure and surface-enhanced Raman scattering (SERS) performance of nanoporous copper (NPC) were investigated. It is found that the microstructure of NPC could be tailored by the ion irradiation dose, i.e., the pore size decreases while the ligament size significantly coarsens with the increase of the irradiation dose. In addition, the SERS enhancement for rhodamine 6G molecules was improved by Au ions irradiation at an appropriate dose. The underlying mechanism of the increase of SERS enhancement resulted from ion irradiation was discussed. Our findings could provide a new way to tune nanoporosity of nanoporous metals and improve their SERS performance.

  8. Charging a Capacitor from an External Fluctuating Potential using a Single Conical Nanopore

    Science.gov (United States)

    Gomez, Vicente; Ramirez, Patricio; Cervera, Javier; Nasir, Saima; Ali, Mubarak; Ensinger, Wolfgang; Mafe, Salvador

    2015-01-01

    We explore the electrical rectification of large amplitude fluctuating signals by an asymmetric nanostructure operating in aqueous solution. We show experimentally and theoretically that a load capacitor can be charged to voltages close to 1 V within a few minutes by converting zero time-average potentials of amplitudes in the range 0.5–3 V into average net currents using a single conical nanopore. This process suggests that significant energy conversion and storage from an electrically fluctuating environment is feasible with a nanoscale pore immersed in a liquid electrolyte solution, a system characteristic of bioelectronics interfaces, electrochemical cells, and nanoporous membranes. PMID:25830563

  9. DNA base-calling from a nanopore using a Viterbi algorithm.

    Science.gov (United States)

    Timp, Winston; Comer, Jeffrey; Aksimentiev, Aleksei

    2012-05-16

    Nanopore-based DNA sequencing is the most promising third-generation sequencing method. It has superior read length, speed, and sample requirements compared with state-of-the-art second-generation methods. However, base-calling still presents substantial difficulty because the resolution of the technique is limited compared with the measured signal/noise ratio. Here we demonstrate a method to decode 3-bp-resolution nanopore electrical measurements into a DNA sequence using a Hidden Markov model. This method shows tremendous potential for accuracy (~98%), even with a poor signal/noise ratio. Copyright © 2012 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  10. Photoluminescence emission of nanoporous anodic aluminum oxide films prepared in phosphoric acid

    Science.gov (United States)

    2012-01-01

    The photoluminescence emission of nanoporous anodic aluminum oxide films formed in phosphoric acid is studied in order to explore their defect-based subband electronic structure. Different excitation wavelengths are used to identify most of the details of the subband states. The films are produced under different anodizing conditions to optimize their emission in the visible range. Scanning electron microscopy investigations confirm pore formation in the produced layers. Gaussian analysis of the emission data indicates that subband states change with anodizing parameters, and various point defects can be formed both in the bulk and on the surface of these nanoporous layers during anodizing. PMID:23272786

  11. Carbon nanotube-based coatings to induce flow enhancement in hydrophilic nanopores

    DEFF Research Database (Denmark)

    Wagemann, Enrique; Walther, Jens Honore; Zambrano, Harvey

    2016-01-01

    With the emergence of the field of nanofluidics, the transport of water in hydrophilic nanopores has attracted intensive research due to its many promising applications. Experiments and simulations have found that flow resistance in hydrophilic nanochannels is much higher than those in macrochann......With the emergence of the field of nanofluidics, the transport of water in hydrophilic nanopores has attracted intensive research due to its many promising applications. Experiments and simulations have found that flow resistance in hydrophilic nanochannels is much higher than those...

  12. Deformation behavior of nano-porous polycrystalline silver. Part II: Simulations

    International Nuclear Information System (INIS)

    Zabihzadeh, S.; Cugnoni, J.; Duarte, L.I.; Van Petegem, S.; Van Swygenhoven, H.

    2017-01-01

    Three-dimensional finite element simulations of nano-porous silver structures are performed to understand the correlation between the porous morphology and the mechanical behavior. The nanostructures have been obtained from ptychographic X-ray computed tomography. The simulations allow distinguishing between the interplay and role of the ligament size, the pore morphology and the porosity, and therefore provide a better comprehension of the experimental observations. We show that the proposed model has a predictive character for mechanical behavior of nano-porous silver.

  13. Research Update: Triblock copolymers as templates to synthesize inorganic nanoporous materials

    Directory of Open Access Journals (Sweden)

    Yunqi Li

    2016-04-01

    Full Text Available This review focuses on the application of triblock copolymers as designed templates to synthesize nanoporous materials with various compositions. Asymmetric triblock copolymers have several advantages compared with symmetric triblock copolymers and diblock copolymers, because the presence of three distinct domains can provide more functional features to direct the resultant nanoporous materials. Here we clearly describe significant contributions of asymmetric triblock copolymers, especially polystyrene-block-poly(2-vinylpyridine-block-poly(ethylene oxide (abbreviated as PS-b-P2VP-b-PEO.

  14. Water desalination with a single-layer MoS2 nanopore

    OpenAIRE

    Heiranian, Mohammad; Farimani, Amir Barati; Aluru, Narayana R.

    2015-01-01

    Efficient desalination of water continues to be a problem facing the society. Advances in nanotechnology have led to the development of a variety of nanoporous membranes for water purification. Here we show, by performing molecular dynamics simulations, that a nanopore in a single-layer molybdenum disulfide can effectively reject ions and allow transport of water at a high rate. More than 88% of ions are rejected by membranes having pore areas ranging from 20 to 60??2. Water flux is found to ...

  15. Spiral silicon drift detectors

    International Nuclear Information System (INIS)

    Rehak, P.; Gatti, E.; Longoni, A.; Sampietro, M.; Holl, P.; Lutz, G.; Kemmer, J.; Prechtel, U.; Ziemann, T.

    1988-01-01

    An advanced large area silicon photodiode (and x-ray detector), called Spiral Drift Detector, was designed, produced and tested. The Spiral Detector belongs to the family of silicon drift detectors and is an improvement of the well known Cylindrical Drift Detector. In both detectors, signal electrons created in silicon by fast charged particles or photons are drifting toward a practically point-like collection anode. The capacitance of the anode is therefore kept at the minimum (0.1pF). The concentric rings of the cylindrical detector are replaced by a continuous spiral in the new detector. The spiral geometry detector design leads to a decrease of the detector leakage current. In the spiral detector all electrons generated at the silicon-silicon oxide interface are collected on a guard sink rather than contributing to the detector leakage current. The decrease of the leakage current reduces the parallel noise of the detector. This decrease of the leakage current and the very small capacities of the detector anode with a capacitively matched preamplifier may improve the energy resolution of Spiral Drift Detectors operating at room temperature down to about 50 electrons rms. This resolution is in the range attainable at present only by cooled semiconductor detectors. 5 refs., 10 figs

  16. Optical Sensors for Biomolecules Using Nanoporous Sol-Gel Materials

    Science.gov (United States)

    Fang, Jonathan; Zhou, Jing C.; Lan, Esther H.; Dunn, Bruce; Gillman, Patricia L.; Smith, Scott M.

    2004-01-01

    An important consideration for space missions to Mars is the ability to detect biosignatures. Solid-state sensing elements for optical detection of biological entities are possible using sol-gel based biologically active materials. We have used these materials as optical sensing elements in a variety of bioassays, including immunoassays and enzyme assays. By immobilizing an appropriate biomolecule in the sol-gel sensing element, we have successfully detected analytes such as amino acids and hormones. In the case of the amino acid glutamate, the enzyme glutamate dehydrogenase was the immobilized molecule, whereas in the case of the hormone cortisol, an anti-cortisol antibody was immobilized in the sensing element. In this previous work with immobilized enzymes and antibodies, excellent sensitivity and specificity were demonstrated in a variety of formats including bulk materials, thin films and fibers. We believe that the sol-gel approach is an attractive platform for bioastronautics sensing applications because of the ability to detect a wide range of entities such as amino acids, fatty acids, hopanes, porphyrins, etc. The sol-gel approach produces an optically transparent 3D silica matrix that forms around the biomolecule of interest, thus stabilizing its structure and functionality while allowing for optical detection. This encapsulation process protects the biomolecule and leads to a more "rugged" sensor. The nanoporous structure of the sol-gel matrix allows diffusion of small target molecules but keeps larger, biomolecules immobilized in the pores. We are currently developing these biologically active sol-gel materials into small portable devices for on-orbit cortisol detection

  17. Neuromorphic Silicon Neuron Circuits

    Science.gov (United States)

    Indiveri, Giacomo; Linares-Barranco, Bernabé; Hamilton, Tara Julia; van Schaik, André; Etienne-Cummings, Ralph; Delbruck, Tobi; Liu, Shih-Chii; Dudek, Piotr; Häfliger, Philipp; Renaud, Sylvie; Schemmel, Johannes; Cauwenberghs, Gert; Arthur, John; Hynna, Kai; Folowosele, Fopefolu; Saighi, Sylvain; Serrano-Gotarredona, Teresa; Wijekoon, Jayawan; Wang, Yingxue; Boahen, Kwabena

    2011-01-01

    Hardware implementations of spiking neurons can be extremely useful for a large variety of applications, ranging from high-speed modeling of large-scale neural systems to real-time behaving systems, to bidirectional brain–machine interfaces. The specific circuit solutions used to implement silicon neurons depend on the application requirements. In this paper we describe the most common building blocks and techniques used to implement these circuits, and present an overview of a wide range of neuromorphic silicon neurons, which implement different computational models, ranging from biophysically realistic and conductance-based Hodgkin–Huxley models to bi-dimensional generalized adaptive integrate and fire models. We compare the different design methodologies used for each silicon neuron design described, and demonstrate their features with experimental results, measured from a wide range of fabricated VLSI chips. PMID:21747754

  18. Silicon containing copolymers

    CERN Document Server

    Amiri, Sahar; Amiri, Sanam

    2014-01-01

    Silicones have unique properties including thermal oxidative stability, low temperature flow, high compressibility, low surface tension, hydrophobicity and electric properties. These special properties have encouraged the exploration of alternative synthetic routes of well defined controlled microstructures of silicone copolymers, the subject of this Springer Brief. The authors explore the synthesis and characterization of notable block copolymers. Recent advances in controlled radical polymerization techniques leading to the facile synthesis of well-defined silicon based thermo reversible block copolymers?are described along with atom transfer radical polymerization (ATRP), a technique utilized to develop well-defined functional thermo reversible block copolymers. The brief also focuses on Polyrotaxanes and their great potential as stimulus-responsive materials which produce poly (dimethyl siloxane) (PDMS) based thermo reversible block copolymers.

  19. Neuromorphic silicon neuron circuits

    Directory of Open Access Journals (Sweden)

    Giacomo eIndiveri

    2011-05-01

    Full Text Available Hardware implementations of spiking neurons can be extremely useful for a large variety of applications, ranging from high-speed modeling of large-scale neural systems to real-time behaving systems, to bidirectional brain-machine interfaces. The specific circuit solutions used to implement silicon neurons depend on the application requirements. In this paper we describe the most common building blocks and techniques used to implement these circuits, and present an overview of a wide range of neuromorphic silicon neurons, which implement different computational models, ranging from biophysically realistic and conductance based Hodgkin-Huxley models to bi-dimensional generalized adaptive Integrate and Fire models. We compare the different design methodologies used for each silicon neuron design described, and demonstrate their features with experimental results, measured from a wide range of fabricated VLSI chips.

  20. Floating Silicon Method

    Energy Technology Data Exchange (ETDEWEB)

    Kellerman, Peter

    2013-12-21

    The Floating Silicon Method (FSM) project at Applied Materials (formerly Varian Semiconductor Equipment Associates), has been funded, in part, by the DOE under a “Photovoltaic Supply Chain and Cross Cutting Technologies” grant (number DE-EE0000595) for the past four years. The original intent of the project was to develop the FSM process from concept to a commercially viable tool. This new manufacturing equipment would support the photovoltaic industry in following ways: eliminate kerf losses and the consumable costs associated with wafer sawing, allow optimal photovoltaic efficiency by producing high-quality silicon sheets, reduce the cost of assembling photovoltaic modules by creating large-area silicon cells which are free of micro-cracks, and would be a drop-in replacement in existing high efficiency cell production process thereby allowing rapid fan-out into the industry.