4,976 research outputs found
Selective Detection of Ethylene Gas Using Carbon Nanotube-based Devices: Utility in Determination of Fruit Ripeness
No full textComparing apples and oranges: A chemoresistive sensor for ethylene can be obtained simply by mixing copper complex 1 with single-walled carbon nanotubes. The resulting devices show sub-ppm sensitivity and high selectivity towards ethylene. The utility of the sensor was demonstrated by following ripening stages in different fruits.United States. Air Force Office of Scientific Research (Contract W911NF-07-D-0004)German Academy of Sciences Leopoldina (Fellowship LPDS 2009-8
Christianus Justus, Ein Zum Namen des Herrn laufender und von ihm beschirmter Gerechter, Wurde Bey Hochansehnlicher Leich-Begängniß Des ... Herrn Christiani Justi Heintzelmanns Hochverdienten Pastoris und Superintendentis der Kirchen und Schulen in Gardelegen und der benachbarten Diœces, Welcher Den 10. Jan. 1717. ... entschlief ... Jn der Furcht des Herrn vorgestellet / Von Joh. Just Meyern, Diacono ad B. M. V.
No full textLeichenpredigt auf Christian Justus Heintzelmann, Pastor u. Superintendent zu Gardelegen, 1664-1717Die Vorlage enth. insgesamt 2 WerkeAutopsie nach Exemplar der ULB Sachsen-AnhaltVorlageform des Erscheinungsvermerks: Helmstädt, gedruckt bey Salomon Schnorrn
Functionalization and applications of CNTs
No full textThesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 2012.Vita. Cataloged from PDF version of thesis.Includes bibliographical references.Carbon nanotubes (CNTs) possess a unique set of electrical and mechanical properties and have been used in a variety of applications. In this thesis, we explore strategies to functionalize CNTs as well as applications which are enabled by functionalized CNTs. Chapter 1 gives an overview of emerging applications of CNTs. In Chapter 2, we describe a route that leads to highly water-soluble multi-walled CNTs (MWCNTs). The good solubility facilitates processing and manipulation of the CNTs. Furthermore, we explore the use of soluble MWCNTs as electrical interconnects in water. Using a Wacker type oxidation reaction, we demonstrate that this type of CNTs can have a positive effect on reactions that involve a metal to metal electron transfer. In Chapter 3, we explore catalytic aziridination reactions to functionalize CNTs as well as [60]fullerene and graphite. In Chapter 4, we use amine functionalized single-walled CNTs (SWCNTs) to attach receptors for gas sensing applications. We optimize the receptors and test the functionalized SWCNTs in an array sensor with regard to sensitivity, selectivity, stability and reproducibility. In Chapter 5, we demonstrate a highly selective sensor for N-methylammonium salts based on SWCNTs that are functionalized with a cavitand. In Chapter 6, we describe a sensor for the plant hormone ethylene. The sensor is based on SWCNTs that are non-covalently functionalized with a copper complex. The device shows good sensitivity and selectivity for ethylene and could be useful in the horticultural industries.by Jan M. Schnorr.Ph.D
Emerging Applications of Carbon Nanotubes
No full textOn the basis of their unique electrical and mechanical properties, carbon nanotubes (CNTs) have attracted great attention in recent years. A diverse array of methods has been developed to modify CNTs and to assemble them into devices. On the basis of these innovations, many applications that include the use of CNTs have been demonstrated. Transparent electrodes for organic light-emitting diodes (OLEDs), lithium-ion batteries, supercapacitors, and CNT-based electronic components such as field-effect transistors (FETs) have been demonstrated. Furthermore, CNTs have been employed in catalysis and sensing as well as filters and mechanical and biomedical applications. This review highlights illustrative examples from these areas to give an overview of applications of CNTs.Massachusetts Institute of Technology. Institute for Soldier Nanotechnologies (DAAD-19-02-0002
Wiring-up catalytically active metals in solution with sulfonated carbon nanotubes
No full textHighly water soluble sulfonate MWCNTs were synthesized and could be used to facilitate the electron transfer between Pd and Cu in a Wacker-type oxidation in solution.United States. Army (Institute for Soldier Nanotechnologies at MIT, DAAD-19-02-0002
Factors affecting the dispersion of MWCNTs in electrically conducting SEBS nanocomposites
No full textThe accessible concentration of exfoliated and undamaged multi-walled carbon nanotubes (MWCNTs) in polymer nanocomposites is an essential issue to the future of these materials. In this work, we report two methodologies directed at obtaining electrically conducting poly(styrene-b-(ethylene-co-butylene)-b- styrene) (SEBS) nanocomposites with different MWCNT contents. The first depends on the time modulation of ultrasonication of toluene mixtures, whereas the second relies on the use of alkyl-functionalized MWCNTs (f-MWCNTs). UV-vis spectroscopy investigations and thermogravimetric analyses allowed the quantification of exfoliated CNTs incorporated in the SEBS mixture. TEM micrographs denoted that a prolonged sonication time (40 min) induced an extensive MWCNTs degradation (average length decreased of 40%), which affected the electrical conductivity of the nanocomposites. The f-MWCNTs appeared to be more effective in preparing SEBS nanocomposites due to the higher dispersion efficiency, negligible nanotube degradation and higher electrical conductivity. The temperature dependence of the resistance of the SEBS/MWCNT system was investigated in the range 20-60 C to explore its potential for sensor development. © 2013 Elsevier B.V. All rights reserved
Cavitand-Functionalized SWCNTs for N-Methylammonium Detection
No full textSingle-walled carbon nanotubes (SWCNTs) have been functionalized with highly selective tetraphosphonate cavitand receptors. The binding of charged N-methylammonium species to the functionalized SWCNTs was analyzed by X-ray photoelectron spectroscopy and confirmed by [superscript 31]P MAS NMR spectroscopy. The cavitand-functionalized SWCNTs were shown to function as chemiresistive sensory materials for the detection of sarcosine and its ethyl ester hydrochloride in water with high selectivity at concentrations as low as 0.02 mM. Exposure to sarcosine and its derivative resulted in an increased conductance, in contrast to a decreased conductance response observed for potential interferents such as the structurally related glycine ethyl ester hydrochloride.European Union. Project BION (ICT-2007-213219)Massachusetts Institute of Technology. Institute for Soldier Nanotechnologies (DAAD-19-02-0002
Mechanical Drawing of Gas Sensors on Paper
No full textPencil it in: Mechanical abrasion of compressed single-walled carbon nanotubes (SWCNTs) on the surface of paper produces sensors capable of detecting NH[subscript 3] gas at sub-ppm concentrations. This method of fabrication is simple, inexpensive, and entirely solvent-free, and avoids difficulties arising from the inherent instability of many SWCNT dispersions.Massachusetts Institute of Technology. Institute for Soldier Nanotechnologies (W911NF-07-D-004)National Institutes of Health (U.S.) (National Cancer Institute (U.S.) Postdoctoral Fellowship Grant F32A1571997
Rapid prototyping of carbon-based chemiresistive gas sensors on paper
No full textChemically functionalized carbon nanotubes (CNTs) are promising materials for sensing of gases and volatile organic compounds. However, the poor solubility of carbon nanotubes hinders their chemical functionalization and the subsequent integration of these materials into devices. This manuscript describes a solvent-free procedure for rapid prototyping of selective chemiresistors from CNTs and graphite on the surface of paper. This procedure enables fabrication of functional gas sensors from commercially available starting materials in less than 15 min. The first step of this procedure involves the generation of solid composites of CNTs or graphite with small molecule selectors—designed to interact with specific classes of gaseous analytes—by solvent-free mechanical mixing in a ball mill and subsequent compression. The second step involves deposition of chemiresistive sensors by mechanical abrasion of these solid composites onto the surface of paper. Parallel fabrication of multiple chemiresistors from diverse composites rapidly generates cross-reactive arrays capable of sensing and differentiating gases and volatile organic compounds at part-per-million and part-per-thousand concentrations.Massachusetts Institute of Technology. Institute for Soldier NanotechnologiesNational Cancer Institute (U.S.) (Ruth L. Kirschstein National Research Service Award F32CA157197
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