scholarly journals Solvent-mediated conductance increase of dodecanethiol-stabilized gold nanoparticle monolayers

2016 ◽  
Vol 7 ◽  
pp. 2057-2064 ◽  
Author(s):  
Patrick A Reissner ◽  
Jean-Nicolas Tisserant ◽  
Antoni Sánchez-Ferrer ◽  
Raffaele Mezzenga ◽  
Andreas Stemmer
Keyword(s):  
Gold Nanoparticle ◽  
Organic Molecules ◽  
Pure Ethanol ◽  
X Ray ◽  
X Ray Scattering ◽  
Average Factor ◽  
Respective Contribution ◽  
Conductance Increase ◽  
Shed Light

Gold nanoparticle monolayers provide convenient templates to study charge transport in organic molecules beyond single junction techniques. Conductance is reported to increase by several orders of magnitude following immersion of alkanethiol-stabilized gold nanoparticle monolayers in a solution containing conjugated thiol-functionalized molecules. Typically, this observation is attributed to molecular exchange. Less attention has been paid to the role of the solvent alone. Here, we report on an increase in conductance of dodecanethiol-stabilized gold nanoparticle monolayers on Si/SiO2 by an average factor of 36 and 22 after immersion in pure ethanol (EtOH) and tetrahydrofuran (THF), respectively. Analysis by scanning electron microscopy (SEM) and small-angle X-ray scattering (SAXS) reveals a solvent-induced decrease in lattice constant of close-packed monolayers. We compare the conductance of the monolayer after molecular exchange with two different oligophenylenes to shed light on the respective contribution of the solvent-induced structural change and the molecular exchange itself on the conductance increase.

scholarly journals Effect of tungsten disulfide nanotubes on crystallization of polylactide under uniaxial deformation and annealing

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Fausta Loffredo ◽  
Loredana Tammaro ◽  
Tiziana Di Luccio ◽  
Carmela Borriello ◽  
Fulvia Villani ◽  
...  
Keyword(s):  
Biomedical Applications ◽  
Structural Evolution ◽  
Tungsten Disulfide ◽  
Fine Tuning ◽  
Nanocomposite Films ◽  
Uniaxial Deformation ◽  
Scanning Calorimetry ◽  
X Ray ◽  
X Ray Scattering

AbstractTungsten disulfide (WS2) nanotubes (NTs) are examined here as a filler for polylactide (PLA) for their ability to accelerate PLA crystallization and for their promising biocompatibility in relevant to biomedical applications of PLA-WS2 nanocomposites. In this work, we have studied the structural and thermal properties of PLA-WS2 nanocomposite films varying the concentration of WS2 NTs from 0 (neat PLA) to 0.6 wt%. The films were uniaxially drawn at 90 °C and annealed at the same temperature for 3 and 10 min. Using wide angle x-ray scattering, Raman spectroscopy and differential scanning calorimetry, we probed the effects of WS2 NT addition on the structure of the PLA films at various stages of processing (unstretched, stretching, annealing). We found that 0.6 wt% of WS2 induces the same level of crystallinity in as stretched PLA-WS2 as annealing in neat PLA for 10 min. These data provide useful insights into the role of WS2 NTs on the structural evolution of PLA-WS2 composites under uniaxial deformation, and extend their applicability to situations where fine tuning of PLA crystallinity is desirable.

scholarly journals Resonant Inelastic X-ray Scattering on Ferrous and Ferric Bis-imidazole Porphyrin and Cytochromec: Nature and Role of the Axial Methionine–Fe Bond

2014 ◽  
Vol 136 (52) ◽  
pp. 18087-18099 ◽  
Author(s):  
Thomas Kroll ◽  
Ryan G. Hadt ◽  
Samuel A. Wilson ◽  
Marcus Lundberg ◽  
James J. Yan ◽  
...  
Keyword(s):  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

scholarly journals Prominent role of oxygen in the multiferroicity ofDyMnO3andTbMnO3: A resonant soft x-ray scattering spectroscopy study

2016 ◽  
Vol 94 (3) ◽  
Author(s):  
S. W. Huang ◽  
J. M. Lee ◽  
Horng-Tay Jeng ◽  
YuCheng Shao ◽  
L. Andrew Wray ◽  
...  
Keyword(s):  
Spectroscopy Study ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

scholarly journals The Role of Intersubunit Interactions for the Stabilization of the T State ofEscherichia coliAspartate Transcarbamoylase

2002 ◽  
Vol 277 (51) ◽  
pp. 49755-49760 ◽  
Author(s):  
Robin S. Chan ◽  
Jessica B. Sakash ◽  
Christine P. Macol ◽  
Jay M. West ◽  
Hiro Tsuruta ◽  
...  
Keyword(s):  
Small Angle ◽  
Structural State ◽  
Aspartate Transcarbamoylase ◽  
Wild Type ◽  
X Ray ◽  
X Ray Scattering ◽  
Intersubunit Interactions ◽  
T State ◽  
Ray Scattering

Homotropic cooperativity inEscherichia coliaspartate transcarbamoylase results from the substrate-induced transition from the T to the R state. These two alternate states are stabilized by a series of interdomain and intersubunit interactions. The salt link between Lys-143 of the regulatory chain and Asp-236 of the catalytic chain is only observed in the T state. When Asp-236 is replaced by alanine the resulting enzyme exhibits full activity, enhanced affinity for aspartate, no cooperativity, and no heterotropic interactions. These characteristics are consistent with an enzyme locked in the functional R state. Using small angle x-ray scattering, the structural consequences of the D236A mutant were characterized. The unliganded D236A holoenzyme appears to be in a new structural state that is neither T, R, nor a mixture of T and R states. The structure of the native D236A holoenzyme is similar to that previously reported for another mutant holoenzyme (E239Q) that also lacks intersubunit interactions. A hybrid version of aspartate transcarbamoylase in which one catalytic subunit was wild-type and the other had the D236A mutation was also investigated. The hybrid holoenzyme, with three of the six possible interactions involving Asp-236, exhibited homotropic cooperativity, and heterotropic interactions consistent with an enzyme with both T and R functional states. Small angle x-ray scattering analysis of the unligated hybrid indicated that the enzyme was in a new structural state more similar to the T than to the R state of the wild-type enzyme. These data suggest that three of the six intersubunit interactions involving D236A are sufficient to stabilize a T-like state of the enzyme and allow for an allosteric transition.

Small angle X-ray scattering coupled with in situ electromechanical probing of nanoparticle-based resistive strain gauges

Nanoscale ◽  
2014 ◽  
Vol 6 (24) ◽  
pp. 15107-15116 ◽  
Author(s):  
Nicolas Decorde ◽  
Neralagatta M. Sangeetha ◽  
Benoit Viallet ◽  
Guillaume Viau ◽  
Jérémie Grisolia ◽  
...  
Keyword(s):  
Gold Nanoparticle ◽  
Small Angle ◽  
Strain Gauges ◽  
Electronic Conduction ◽  
X Ray ◽  
X Ray Scattering ◽  
Mechanisms Of Deformation ◽  
Ray Scattering

SAXS/GISAXS, electromechanical tests and simulations on electronic conduction are carried out on gold nanoparticle-based strain gauges to unravel the mechanisms of deformation.

Characterizing the Structure of Organic Molecules of Intrinsic Microporosity by Molecular Simulations and X-ray Scattering

2012 ◽  
Vol 117 (1) ◽  
pp. 355-364 ◽  
Author(s):  
Lauren J. Abbott ◽  
Amanda G. McDermott ◽  
Annalaura Del Regno ◽  
Rupert G. D. Taylor ◽  
C. Grazia Bezzu ◽  
...  
Keyword(s):  
Organic Molecules ◽  
Molecular Simulations ◽  
X Ray ◽  
X Ray Scattering ◽  
Intrinsic Microporosity ◽  
Ray Scattering

scholarly journals A dilute gold nanoparticle suspension as small-angle X-ray scattering standard for an absolute scale using an extended Guinier approximation

2019 ◽  
Vol 52 (2) ◽  
pp. 344-350 ◽  
Author(s):  
Ahmed S. A. Mohammed ◽  
Agnese Carino ◽  
Andrea Testino ◽  
Mohammad Reza Andalibi ◽  
Antonio Cervellino
Keyword(s):  
Gold Nanoparticle ◽  
Small Angle ◽  
Order Term ◽  
Absolute Intensity ◽  
Nanoparticle Suspension ◽  
X Ray ◽  
Practical Procedure ◽  
X Ray Scattering ◽  
Angle Scattering ◽  
Liquid Microjets

In this article, a practical procedure for absolute intensity calibration for small-angle scattering (SAXS) studies on liquid microjets is established. A gold nanoparticle suspension is used as standard so that the intercept at Q = 0 of the SAXS scattering curve provides a scaling reference. In order to obtain the most precise extrapolation at Q = 0, an extension of the Guinier approximation has been used, with a second-order term in the fit that adapts to a larger Q range.

Small-Angle X-Ray Scattering for the Discerning Macromolecular Crystallographer

2014 ◽  
Vol 67 (12) ◽  
pp. 1786 ◽  
Author(s):  
Lachlan W. Casey ◽  
Alan E. Mark ◽  
Bostjan Kobe
Keyword(s):  
Structural Biology ◽  
Small Angle ◽  
Significant Risk ◽  
Macromolecular Crystallography ◽  
Saxs Data ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

The role of small-angle X-ray scattering (SAXS) in structural biology is now well established, and its usefulness in combination with macromolecular crystallography is clear. However, the highly averaged SAXS data present a significant risk of over-interpretation to the unwary practitioner, and it can be challenging to frame SAXS results in a manner that maximises the reliability of the conclusions drawn. In this review, a series of recent examples are used to illustrate both the challenges for interpretation and approaches through which these can be overcome.

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