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Chan DH, Wills JL, Tandy JD, Burchell MJ, Wozniakiewicz PJ, Alesbrook LS, Armes SP. Synthesis of Autofluorescent Phenanthrene Microparticles via Emulsification: A Useful Synthetic Mimic for Polycyclic Aromatic Hydrocarbon-Based Cosmic Dust. ACS APPLIED MATERIALS & INTERFACES 2023; 15:54039-54049. [PMID: 37944021 PMCID: PMC10685351 DOI: 10.1021/acsami.3c08585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 10/19/2023] [Accepted: 10/24/2023] [Indexed: 11/12/2023]
Abstract
Phenanthrene is the simplest example of a polycyclic aromatic hydrocarbon (PAH). Herein, we exploit its relatively low melting point (101 °C) to prepare microparticles from molten phenanthrene droplets by conducting high-shear homogenization in a 3:1 water/ethylene glycol mixture at 105 °C using poly(N-vinylpyrrolidone) as a non-ionic polymeric emulsifier. Scanning electron microscopy studies confirm that this protocol produces polydisperse phenanthrene microparticles with a spherical morphology: laser diffraction studies indicate a volume-average diameter of 25 ± 21 μm. Such projectiles are fired into an aluminum foil target at 1.87 km s-1 using a two-stage light gas gun. Interestingly, the autofluorescence exhibited by phenanthrene aids analysis of the resulting impact craters. More specifically, it enables assessment of the spatial distribution of any surviving phenanthrene in the vicinity of each crater. Furthermore, these phenanthrene microparticles can be coated with an ultrathin overlayer of polypyrrole, which reduces their autofluorescence. In principle, such core-shell microparticles should be useful for assessing the extent of thermal ablation that is likely to occur when they are fired into aerogel targets. Accordingly, polypyrrole-coated microparticles were fired into an aerogel target at 2.07 km s-1. Intact microparticles were identified at the end of carrot tracks and their relatively weak autofluorescence suggests that thermal ablation during aerogel capture did not completely remove the polypyrrole overlayer. Thus, these new core-shell microparticles appear to be useful model projectiles for assessing the extent of thermal processing that can occur in such experiments, which have implications for the capture of intact PAH-based dust grains originating from cometary tails or from plumes emanating from icy satellites (e.g., Enceladus) in future space missions.
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Affiliation(s)
- Derek
H. H. Chan
- Dainton
Building, Department of Chemistry, University
of Sheffield, Brook Hill, Sheffield, South
Yorkshire S3 7HF, U.K.
| | - Jessica L. Wills
- School
of Physics and Astronomy, University of
Kent, Canterbury, Kent CT2 7NH, U.K.
| | - Jon D. Tandy
- School
of Chemistry and Forensic Science, University
of Kent, Canterbury, Kent CT2 7NZ, U.K.
| | - Mark J. Burchell
- School
of Physics and Astronomy, University of
Kent, Canterbury, Kent CT2 7NH, U.K.
| | | | - Luke S. Alesbrook
- School
of Physics and Astronomy, University of
Kent, Canterbury, Kent CT2 7NH, U.K.
| | - Steven P. Armes
- Dainton
Building, Department of Chemistry, University
of Sheffield, Brook Hill, Sheffield, South
Yorkshire S3 7HF, U.K.
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2
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Dannenmann M, Klenner F, Bönigk J, Pavlista M, Napoleoni M, Hillier J, Khawaja N, Olsson-Francis K, Cable ML, Malaska MJ, Abel B, Postberg F. Toward Detecting Biosignatures of DNA, Lipids, and Metabolic Intermediates from Bacteria in Ice Grains Emitted by Enceladus and Europa. ASTROBIOLOGY 2023; 23:60-75. [PMID: 36454287 DOI: 10.1089/ast.2022.0063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
The reliable identification of biosignatures is key to the search for life elsewhere. On ocean worlds like Enceladus or Europa, this can be achieved by impact ionization mass spectrometers, such as the SUrface Dust Analyzer (SUDA) on board NASA's upcoming Europa Clipper mission. During spacecraft flybys, these instruments can sample ice grains formed from subsurface water and emitted by these moons. Previous laboratory analog experiments have demonstrated that SUDA-type instruments could identify amino acids, fatty acids, and peptides in ice grains and discriminate between their abiotic and biotic origins. Here, we report experiments simulating impact ionization mass spectra of ice grains containing DNA, lipids, and metabolic intermediates extracted from two bacterial cultures: Escherichia coli and Sphingopyxis alaskensis. Salty Enceladan or Europan ocean waters were simulated using matrices with different NaCl concentrations. Characteristic mass spectral signals, such as DNA nucleobases, are clearly identifiable at part-per-million-level concentrations. Mass spectra of all substances exhibit unambiguous biogenic patterns, which in some cases show significant differences between the two bacterial species. Sensitivity to the biosignatures decreases with increasing matrix salinity. The experimental parameters indicate that future impact ionization mass spectrometers will be most sensitive to the investigated biosignatures for ice grain encounter speeds of 4-6 km/s.
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Affiliation(s)
- Marie Dannenmann
- Institute of Geological Sciences, Freie Universität Berlin, Berlin, Germany
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
| | - Fabian Klenner
- Institute of Geological Sciences, Freie Universität Berlin, Berlin, Germany
| | - Janine Bönigk
- Institute of Geological Sciences, Freie Universität Berlin, Berlin, Germany
| | - Miriam Pavlista
- Institute of Geological Sciences, Freie Universität Berlin, Berlin, Germany
| | - Maryse Napoleoni
- Institute of Geological Sciences, Freie Universität Berlin, Berlin, Germany
| | - Jon Hillier
- Institute of Geological Sciences, Freie Universität Berlin, Berlin, Germany
| | - Nozair Khawaja
- Institute of Geological Sciences, Freie Universität Berlin, Berlin, Germany
| | - Karen Olsson-Francis
- AstrobiologyOU, Faculty of Science, Technology, Engineering & Mathematics, The Open University, Milton Keynes, United Kingdom
| | - Morgan L Cable
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
| | - Michael J Malaska
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
| | - Bernd Abel
- Leibniz-Institute of Surface Engineering (IOM), Leipzig, Germany
- Wilhelm-Ostwald-Institute for Physical and Theoretical Chemistry, Leipzig University, Leipzig, Germany
| | - Frank Postberg
- Institute of Geological Sciences, Freie Universität Berlin, Berlin, Germany
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3
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Jaramillo-Botero A, Cable ML, Hofmann AE, Malaska M, Hodyss R, Lunine J. Understanding Hypervelocity Sampling of Biosignatures in Space Missions. ASTROBIOLOGY 2021; 21:421-442. [PMID: 33749334 PMCID: PMC7994429 DOI: 10.1089/ast.2020.2301] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 11/09/2020] [Indexed: 05/08/2023]
Abstract
The atomic-scale fragmentation processes involved in molecules undergoing hypervelocity impacts (HVIs; defined as >3 km/s) are challenging to investigate via experiments and still not well understood. This is particularly relevant for the consistency of biosignals from small-molecular-weight neutral organic molecules obtained during solar system robotic missions sampling atmospheres and plumes at hypervelocities. Experimental measurements to replicate HVI effects on neutral molecules are challenging, both in terms of accelerating uncharged species and isolating the multiple transition states over very rapid timescales (<1 ps). Nonequilibrium first-principles-based simulations extend the range of what is possible with experiments. We report on high-fidelity simulations of the fragmentation of small organic biosignature molecules over the range v = 1-12 km/s, and demonstrate that the fragmentation fraction is a sensitive function of velocity, impact angle, molecular structure, impact surface material, and the presence of surrounding ice shells. Furthermore, we generate interpretable fragmentation pathways and spectra for velocity values above the fragmentation thresholds and reveal how organic molecules encased in ice grains, as would likely be the case for those in "ocean worlds," are preserved at even higher velocities than bare molecules. Our results place ideal spacecraft encounter velocities between 3 and 5 km/s for bare amino and fatty acids and within 4-6 km/s for the same species encased in ice grains and predict the onset of organic fragmentation in ice grains at >5 km/s, both consistent with recent experiments exploring HVI effects using impact-induced ionization and analysis via mass spectrometry and from the analysis of Enceladus organics in Cassini Data. From nanometer-sized ice Ih clusters, we establish that HVI energy is dissipated by ice casings through thermal resistance to the impact shock wave and that an upper fragmentation velocity limit exists at which ultimately any organic contents will be cleaved by the surrounding ice-this provides a fundamental path to characterize micrometer-sized ice grains. Altogether, these results provide quantifiable insights to bracket future instrument design and mission parameters.
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Affiliation(s)
- Andres Jaramillo-Botero
- Chemistry and Chemical Engineering Division, California Institute of Technology, Pasadena, California, USA
| | - Morgan L. Cable
- NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
| | - Amy E. Hofmann
- NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
| | - Michael Malaska
- NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
| | - Robert Hodyss
- NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
| | - Jonathan Lunine
- Department of Astronomy and Carl Sagan Institute, Cornell University, Ithaca, New York, USA
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4
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Chan DH, Millet A, Fisher CR, Price MC, Burchell MJ, Armes SP. Synthesis and Characterization of Polypyrrole-Coated Anthracene Microparticles: A New Synthetic Mimic for Polyaromatic Hydrocarbon-Based Cosmic Dust. ACS APPLIED MATERIALS & INTERFACES 2021; 13:3175-3185. [PMID: 33405514 PMCID: PMC7880557 DOI: 10.1021/acsami.0c19758] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Accepted: 12/24/2020] [Indexed: 06/12/2023]
Abstract
Polyaromatic hydrocarbons (PAHs) are found throughout the universe. The ubiquity of these organic molecules means that they are of considerable interest in the context of cosmic dust, which typically travels at hypervelocities (>1 km s-1) within our solar system. However, studying such fast-moving micrometer-sized particles in laboratory-based experiments requires suitable synthetic mimics. Herein, we use ball-milling to produce microparticles of anthracene, which is the simplest member of the PAH family. Size control can be achieved by varying the milling time in the presence of a suitable anionic commercial polymeric dispersant (Morwet D-425). These anthracene microparticles are then coated with a thin overlayer of polypyrrole (PPy), which is an air-stable organic conducting polymer. The uncoated and PPy-coated anthracene microparticles are characterized in terms of their particle size, surface morphology, and chemical structure using optical microscopy, scanning electron microscopy, laser diffraction, aqueous electrophoresis, FT-IR spectroscopy, Raman microscopy, and X-ray photoelectron spectroscopy (XPS). Moreover, such microparticles can be accelerated up to hypervelocities using a light gas gun. Finally, studies of impact craters indicate carbon debris, so they are expected to serve as the first synthetic mimic for PAH-based cosmic dust.
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Affiliation(s)
- Derek H. Chan
- Department of Chemistry, University of
Sheffield, Dainton Building, Brook Hill, Sheffield, South Yorkshire S3
7HF, U.K.
| | - Arthur Millet
- Department of Chemistry, University of
Sheffield, Dainton Building, Brook Hill, Sheffield, South Yorkshire S3
7HF, U.K.
| | - Callum R. Fisher
- Centre for Astrophysics and Planetary Science, School
of Physical Sciences, University of Kent, Ingram Building,
Canterbury, Kent CT2 7NH, U.K.
| | - Mark C. Price
- Centre for Astrophysics and Planetary Science, School
of Physical Sciences, University of Kent, Ingram Building,
Canterbury, Kent CT2 7NH, U.K.
| | - Mark J. Burchell
- Centre for Astrophysics and Planetary Science, School
of Physical Sciences, University of Kent, Ingram Building,
Canterbury, Kent CT2 7NH, U.K.
| | - Steven P. Armes
- Department of Chemistry, University of
Sheffield, Dainton Building, Brook Hill, Sheffield, South Yorkshire S3
7HF, U.K.
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5
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Postberg F, Khawaja N, Abel B, Choblet G, Glein CR, Gudipati MS, Henderson BL, Hsu HW, Kempf S, Klenner F, Moragas-Klostermeyer G, Magee B, Nölle L, Perry M, Reviol R, Schmidt J, Srama R, Stolz F, Tobie G, Trieloff M, Waite JH. Macromolecular organic compounds from the depths of Enceladus. Nature 2018; 558:564-568. [PMID: 29950623 PMCID: PMC6027964 DOI: 10.1038/s41586-018-0246-4] [Citation(s) in RCA: 83] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 03/23/2018] [Indexed: 11/13/2022]
Abstract
Saturn's moon Enceladus harbours a global water ocean 1 , which lies under an ice crust and above a rocky core 2 . Through warm cracks in the crust 3 a cryo-volcanic plume ejects ice grains and vapour into space4-7 that contain materials originating from the ocean8,9. Hydrothermal activity is suspected to occur deep inside the porous core10-12, powered by tidal dissipation 13 . So far, only simple organic compounds with molecular masses mostly below 50 atomic mass units have been observed in plume material6,14,15. Here we report observations of emitted ice grains containing concentrated and complex macromolecular organic material with molecular masses above 200 atomic mass units. The data constrain the macromolecular structure of organics detected in the ice grains and suggest the presence of a thin organic-rich film on top of the oceanic water table, where organic nucleation cores generated by the bursting of bubbles allow the probing of Enceladus' organic inventory in enhanced concentrations.
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Affiliation(s)
- Frank Postberg
- Institut für Geowissenschaften, Universität Heidelberg, Heidelberg, Germany.
- Klaus-Tschira-Labor für Kosmochemie, Universität Heidelberg, Heidelberg, Germany.
- Institut für Geologische Wissenschaften, Freie Universität Berlin, Berlin, Germany.
| | - Nozair Khawaja
- Institut für Geowissenschaften, Universität Heidelberg, Heidelberg, Germany
| | - Bernd Abel
- Leibniz-Institute für Oberflächenmodifizierung (IOM), Leipzig, Germany
| | - Gael Choblet
- Laboratoire de Planétologie et Géodynamique, UMR-CNRS 6112, Université de Nantes, Nantes, France
| | - Christopher R Glein
- Space Science and Engineering Division, Southwest Research Institute, San Antonio, TX, USA
| | - Murthy S Gudipati
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - Bryana L Henderson
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
| | - Hsiang-Wen Hsu
- Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO, USA
| | - Sascha Kempf
- Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO, USA
| | - Fabian Klenner
- Institut für Geowissenschaften, Universität Heidelberg, Heidelberg, Germany
| | | | - Brian Magee
- Space Science and Engineering Division, Southwest Research Institute, San Antonio, TX, USA
- Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO, USA
| | - Lenz Nölle
- Institut für Geowissenschaften, Universität Heidelberg, Heidelberg, Germany
| | - Mark Perry
- Applied Physics Laboratory, Johns Hopkins University, Laurel, MD, USA
| | - René Reviol
- Institut für Geowissenschaften, Universität Heidelberg, Heidelberg, Germany
| | - Jürgen Schmidt
- Astronomy Research Unit, University of Oulu, Oulu, Finland
| | - Ralf Srama
- Institut für Raumfahrtsysteme, Universität Stuttgart, Stuttgart, Germany
| | - Ferdinand Stolz
- Leibniz-Institute für Oberflächenmodifizierung (IOM), Leipzig, Germany
- Wilhelm-Ostwald-Institut für Physikalische und Theoretische Chemie, Universität Leipzig, Leipzig, Germany
| | - Gabriel Tobie
- Laboratoire de Planétologie et Géodynamique, UMR-CNRS 6112, Université de Nantes, Nantes, France
| | - Mario Trieloff
- Institut für Geowissenschaften, Universität Heidelberg, Heidelberg, Germany
- Klaus-Tschira-Labor für Kosmochemie, Universität Heidelberg, Heidelberg, Germany
| | - J Hunter Waite
- Laboratoire de Planétologie et Géodynamique, UMR-CNRS 6112, Université de Nantes, Nantes, France
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6
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Fielding LA, Hillier JK, Burchell MJ, Armes SP. Space science applications for conducting polymer particles: synthetic mimics for cosmic dust and micrometeorites. Chem Commun (Camb) 2015; 51:16886-99. [DOI: 10.1039/c5cc07405c] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The design of conducting polymer-based particles as synthetic mimics for understanding the behaviour of micro-meteorites (a.k.a. cosmic dust) is reviewed and the implications for various space science applications is discussed.
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Affiliation(s)
| | - Jon K. Hillier
- Department of Space Science
- School of Physical Sciences
- University of Kent
- Canterbury
- UK
| | - Mark J. Burchell
- Department of Space Science
- School of Physical Sciences
- University of Kent
- Canterbury
- UK
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7
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Hillier JK, Postberg F, Sestak S, Srama R, Kempf S, Trieloff M, Sternovsky Z, Green SF. Impact ionization mass spectra of anorthite cosmic dust analogue particles. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2012je004077] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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8
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Debord JD, Della-Negra S, Fernandez-Lima FA, Verkhoturov SV, Schweikert EA. Bi-Directional Ion Emission from Massive Gold Cluster Impacts on Nanometric Carbon Foils. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2012; 116:8138-8144. [PMID: 22888385 PMCID: PMC3413922 DOI: 10.1021/jp212126m] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Carbon cluster emission from thin carbon foils (5-40 nm) impacted by individual Au(n) (+q) cluster projectiles (95-125 qkeV, n/q = 3-200) reveals features regarding the energy deposition, projectile range, and projectile fate in matter as a function of the projectile characteristics. For the first time, the secondary ion emission from thin foils has been monitored simultaneously in both forward and backward emission directions. The projectile range and depth of emission were examined as a function of projectile size, energy, and target thickness. A key finding is that the massive cluster impact develops very differently from that of a small polyatomic projectile. The range of the 125 qkeV Au(100q) (+q) (q ≈ 4) projectile is estimated to be 20 nm (well beyond the range of an equal velocity Au(+)) and projectile disintegration occurs at the exit of even a 5 nm thick foil.
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Affiliation(s)
- J Daniel Debord
- Department of Chemistry, Texas A&M University, College Station, Texas 77943-3144
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9
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Austin DE, Shen AHT, Beauchamp JL, Ahrens TJ. Time-of-flight mass spectrometry of mineral volatilization: toward direct composition analysis of shocked mineral vapor. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2012; 83:044502. [PMID: 22559558 DOI: 10.1063/1.4705745] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We have developed an orthogonal-acceleration time-of-flight mass spectrometer to study the volatiles produced when a mineral's shock-compressed state is isentropically released, as occurs when a shock wave, driven into the mineral by an impact, reflects upon reaching a free surface. The instrument is designed to use a gun or explosive-launched projectile as the source of the shock wave, impact onto a flange separating a poor vacuum and the high vacuum (10(-7) Torr) interior of the mass spectrometer, and transmission of the shock wave through the flange to a mineral sample mounted on the high-vacuum side of the flange. The device extracts and analyzes the neutrals and ions produced from the shocked mineral prior to the possible occurrence of collateral instrument damage from the shock-inducing impact. The instrument has been tested using laser ablation of various mineral surfaces, and the resulting spectra are presented. Mass spectra are compared with theoretical distributions of molecular species, and with expected distributions from laser desorption.
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Affiliation(s)
- Daniel E Austin
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA.
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10
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Fielding LA, Armes SP. Preparation of Pickering emulsions and colloidosomes using either a glycerol-functionalised silica sol or core–shell polymer/silica nanocomposite particles. ACTA ACUST UNITED AC 2012. [DOI: 10.1039/c2jm31433a] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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11
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Hsu HW, Postberg F, Kempf S, Trieloff M, Burton M, Roy M, Moragas-Klostermeyer G, Srama R. Stream particles as the probe of the dust-plasma-magnetosphere interaction at Saturn. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2011ja016488] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- H.-W. Hsu
- MPI für Kernphysik; Heidelberg Germany
- Institut für Geowissenschaften; Ruprecht-Karls Universität; Heidelberg Germany
- Laboratory for Atmospheric and Space Physics; University of Colorado; Boulder Colorado USA
| | - F. Postberg
- MPI für Kernphysik; Heidelberg Germany
- Institut für Geowissenschaften; Ruprecht-Karls Universität; Heidelberg Germany
| | - S. Kempf
- MPI für Kernphysik; Heidelberg Germany
- Laboratory for Atmospheric and Space Physics; University of Colorado; Boulder Colorado USA
- Institut für Geophysik und Extraterrestrische Physik; Universität Braunschweig; Braunschweig Germany
| | - M. Trieloff
- Institut für Geowissenschaften; Ruprecht-Karls Universität; Heidelberg Germany
| | - M. Burton
- Jet Propulsion Laboratory; Pasadena California USA
| | - M. Roy
- Jet Propulsion Laboratory; Pasadena California USA
| | - G. Moragas-Klostermeyer
- MPI für Kernphysik; Heidelberg Germany
- Laboratory for Atmospheric and Space Physics; University of Colorado; Boulder Colorado USA
| | - R. Srama
- MPI für Kernphysik; Heidelberg Germany
- Institut für Raumfahrtsysteme; Universität Stuttgart; Stuttgart Germany
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12
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Mocker A, Bugiel S, Auer S, Baust G, Colette A, Drake K, Fiege K, Grün E, Heckmann F, Helfert S, Hillier J, Kempf S, Matt G, Mellert T, Munsat T, Otto K, Postberg F, Röser HP, Shu A, Sternovsky Z, Srama R. A 2 MV Van de Graaff accelerator as a tool for planetary and impact physics research. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2011; 82:095111. [PMID: 21974623 DOI: 10.1063/1.3637461] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Investigating the dynamical and physical properties of cosmic dust can reveal a great deal of information about both the dust and its many sources. Over recent years, several spacecraft (e.g., Cassini, Stardust, Galileo, and Ulysses) have successfully characterised interstellar, interplanetary, and circumplanetary dust using a variety of techniques, including in situ analyses and sample return. Charge, mass, and velocity measurements of the dust are performed either directly (induced charge signals) or indirectly (mass and velocity from impact ionisation signals or crater morphology) and constrain the dynamical parameters of the dust grains. Dust compositional information may be obtained via either time-of-flight mass spectrometry of the impact plasma or direct sample return. The accurate and reliable interpretation of collected spacecraft data requires a comprehensive programme of terrestrial instrument calibration. This process involves accelerating suitable solar system analogue dust particles to hypervelocity speeds in the laboratory, an activity performed at the Max Planck Institut für Kernphysik in Heidelberg, Germany. Here, a 2 MV Van de Graaff accelerator electrostatically accelerates charged micron and submicron-sized dust particles to speeds up to 80 km s(-1). Recent advances in dust production and processing have allowed solar system analogue dust particles (silicates and other minerals) to be coated with a thin conductive shell, enabling them to be charged and accelerated. Refinements and upgrades to the beam line instrumentation and electronics now allow for the reliable selection of particles at velocities of 1-80 km s(-1) and with diameters of between 0.05 μm and 5 μm. This ability to select particles for subsequent impact studies based on their charges, masses, or velocities is provided by a particle selection unit (PSU). The PSU contains a field programmable gate array, capable of monitoring in real time the particles' speeds and charges, and is controlled remotely by a custom, platform independent, software package. The new control instrumentation and electronics, together with the wide range of accelerable particle types, allow the controlled investigation of hypervelocity impact phenomena across a hitherto unobtainable range of impact parameters.
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Affiliation(s)
- Anna Mocker
- IRS, Universität Stuttgart, Pfaffenwaldring 31, D-70569 Stuttgart, Germany.
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13
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Burchell MJ, Armes SP. Impact ionisation spectra from hypervelocity impacts using aliphatic poly(methyl methacrylate) microparticle projectiles. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2011; 25:543-550. [PMID: 21259363 DOI: 10.1002/rcm.4887] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We report impact ionisation spectra from spherical poly(methyl methacrylate) (PMMA) microparticles of 724 nm diameter impacting a rhodium target. These projectiles were coated with an ultrathin (~11 nm) overlayer of polypyrrole, an electrically conducting organic polymer; this enabled the accumulation of sufficient surface charge to allow electrostatic acceleration up to speeds of 4 to 8 km s(-1) using a high-voltage Van de Graaff instrument. A grid above the target (held at 3.33 kV cm(-1) with respect to the target) accelerated the cations that were generated during the hypervelocity impacts, and these ions then drifted to a charge detector. By measuring the collected charge vs. time and assuming only single ionisation events, time-of-flight mass spectra were obtained. Strong signals were observed for cationic species with ions of m/z 41, 65 and 115. There were also minor contributions from cations with masses ranging from m/z 29 to 142. The three major signals are assigned to fragment ions (C(3)H(5)(+), C(4)H(5)O(+)/C(5)H(9)(+) and C(6)H(11)O(2)(+)) which are known to be associated with the decomposition of PMMA. These impact ionisation spectra differ significantly from those reported earlier using polystyrene (PS) microparticles. The aliphatic PMMA microparticles generate small (m/z <100) fragment ions more readily at lower speeds than the predominantly aromatic PS microparticles, where speeds of at least 10 km s(-1) are typically required for substantial yields of low-mass fragment ions. This correlates well with the well-known greater chemical and thermal fragility of PMMA compared to PS. The PMMA microparticles should prove useful synthetic mimics for aliphatic carbonaceous micrometeorites.
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Affiliation(s)
- Mark J Burchell
- Centre for Astrophysics and Planetary Science, School of Physical Sciences, Ingram Building, University of Kent, Canterbury CT2 7NH, UK.
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14
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Madani A, Nessark B, Brayner R, Elaissari H, Jouini M, Mangeney C, Chehimi MM. Carboxylic acid-functionalized, core–shell polystyrene@polypyrrole microspheres as platforms for the attachment of CdS nanoparticles. POLYMER 2010. [DOI: 10.1016/j.polymer.2010.04.020] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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15
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Affiliation(s)
- Steffen M. Weidner
- Federal Institute for Materials Research and Testing (BAM), D-12489 Berlin, Richard-Willstaetter-Strasse 11, Germany, and Department of Chemistry, Wayne State University, 5101 Cass Avenue, 33 Chemistry, Detroit, Michigan 48202
| | - Sarah Trimpin
- Federal Institute for Materials Research and Testing (BAM), D-12489 Berlin, Richard-Willstaetter-Strasse 11, Germany, and Department of Chemistry, Wayne State University, 5101 Cass Avenue, 33 Chemistry, Detroit, Michigan 48202
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