New Modular Calamitic Ligands for Self-Assembly of Thermostable Quantum Dot Microcapsules via Nematic Templating

2018 ◽  
Author(s):  
Amir Keshavarz ◽  
Sheida Riahinasab ◽  
Linda Hirst ◽  
Ben Stokes
Keyword(s):  
Quantum Dot ◽  
Self Assembly ◽  
Organic Ligands ◽  
Interparticle Spacing ◽  
Design Synthesis ◽  
X Ray ◽  
New Class ◽  
X Ray Scattering ◽  
Synthesis Properties ◽  
And Performance

The design, synthesis, properties, and performance of a new class of promesogenic calamitic side-tethering organic ligands used to direct quantum dot nanoparticle self-assembly via nematic templating are described. This work was motivated by inadequate modularity, step count, and yield associated with syntheses of existing ligands. Attaching the new ligands to quantum dots and dispersing them in a liquid crystal host affords hollow micron-sized capsules via nematic templating. The capsules resist thermal decomposition up to 350 °C — significantly higher than any previously reported microcapsules assembled from side-tethering calamitic ligand-functionalized nanoparticle. Evaluation of the capsules by small-angle X-ray scattering shows that interparticle spacing varies from 10–13 nm depending on the ligand used, and is correlated to aminoalkyl chain length.

New Modular Calamitic Ligands for Self-Assembly of Thermostable Quantum Dot Microcapsules via Nematic Templating

2018 ◽  
Author(s):  
Amir Keshavarz ◽  
Sheida Riahinasab ◽  
Linda Hirst ◽  
Ben Stokes
Keyword(s):  
Quantum Dot ◽  
Self Assembly ◽  
Organic Ligands ◽  
Interparticle Spacing ◽  
Design Synthesis ◽  
X Ray ◽  
New Class ◽  
X Ray Scattering ◽  
Synthesis Properties ◽  
And Performance

The design, synthesis, properties, and performance of a new class of promesogenic calamitic side-tethering organic ligands used to direct quantum dot nanoparticle self-assembly via nematic templating are described. This work was motivated by inadequate modularity, step count, and yield associated with syntheses of existing ligands. Attaching the new ligands to quantum dots and dispersing them in a liquid crystal host affords hollow micron-sized capsules via nematic templating. The capsules resist thermal decomposition up to 350 °C — significantly higher than any previously reported microcapsules assembled from side-tethering calamitic ligand-functionalized nanoparticle. Evaluation of the capsules by small-angle X-ray scattering shows that interparticle spacing varies from 10–13 nm depending on the ligand used, and is correlated to aminoalkyl chain length.

Structure of Cobalt Nanosphere Superlattice Films by Small Angle X-ray Scattering

2004 ◽  
Vol 818 ◽  
Author(s):  
Michael Beerman ◽  
Masato Ohnuma ◽  
Yuping Bao ◽  
Kannan M. Krishnan
Keyword(s):  
Small Angle ◽  
Self Assembly ◽  
The Self ◽  
Interparticle Spacing ◽  
Face Centered Cubic ◽  
X Ray ◽  
X Ray Scattering ◽  
Least Squares Fit ◽  
Wide Range ◽  
Ray Scattering

AbstractCobalt nanocrystals, recently synthesized with narrow size distributions and controlled shapes, organize in a wide range of arrays as a function of shape, size and interparticle interactions. The nanocrystals (NCs) consist of a cobalt metal core with a nominal diameter of 11 nm, and an organic surfactant surface layer with a chain length of ∼1.7 nm. For the simplest case (ε-Co nanospheres, super-paramagnetic at room temperature) a hexagonal arrangement of NCs is observed in transmission electron microscope (TEM) images when precipitated from solution onto carbon films. For practical applications and for further understanding of the self-assembly process, long range order of the super lattice must be probed over regions that are greater in extent than may be examined by TEM. Hence, small angle x-ray scattering (SAXS) measurements were performed on cobalt nanospheres randomly dispersed in solution and assembled on glass substrates. Least squares fit to the intensity distribution as a function of the scattering vector q gave an average particle diameter of 11.0 ± 0.8 nm. Structure factor contribution to the intensity profile agrees well with a quasi-random model for scattering from a face centered cubic (FCC) superlattice composed of uniform radius cobalt spheres. The measured nearest neighbor interparticle spacing, 14.1 nm, agrees to within 2% of the predicted value of 14.4 nm based on a free energy model that governs the self-assembly of the nanoparticle system.

scholarly journals Templating growth of gold nanostructures with a CdSe quantum dot array

Nanoscale ◽  
2015 ◽  
Vol 7 (21) ◽  
pp. 9703-9714 ◽  
Author(s):  
Neelima Paul ◽  
Ezzeldin Metwalli ◽  
Yuan Yao ◽  
Matthias Schwartzkopf ◽  
Shun Yu ◽  
...  
Keyword(s):  
Quantum Dot ◽  
Self Assembly ◽  
Grazing Incidence ◽  
Gold Nanostructures ◽  
X Ray ◽  
X Ray Scattering ◽  
Gold Sputtering ◽  
Gold Nanostructure ◽  
Time Observation ◽  
Real Time Observation

The controlled gold sputtering on quantum dot arrays forms gold nanostructures exclusively on top of quantum dots by self-assembly. A real time observation of the gold nanostructure growth is enabled with grazing incidence small-angle X-ray scattering (GISAXS).

In situ Time-Resolved Small-Angle X-ray Scattering Reveals the Formation Kinetics of Polyelectrolyte Complex Micelles

2019 ◽  
Author(s):  
Hao Wu ◽  
Jeffrey Ting ◽  
Siqi Meng ◽  
Matthew Tirrell
Keyword(s):  
Small Angle ◽  
Self Assembly ◽  
Electrostatic Interactions ◽  
Polyelectrolyte Complex ◽  
Time Resolved ◽  
X Ray ◽  
X Ray Scattering ◽  
Kinetics Of ◽  
Ray Scattering

We have directly observed the <i>in situ</i> self-assembly kinetics of polyelectrolyte complex (PEC) micelles by synchrotron time-resolved small-angle X-ray scattering, equipped with a stopped-flow device that provides millisecond temporal resolution. This work has elucidated one general kinetic pathway for the process of PEC micelle formation, which provides useful physical insights for increasing our fundamental understanding of complexation and self-assembly dynamics driven by electrostatic interactions that occur on ultrafast timescales.

scholarly journals Alpha helical surfactant-like peptides self-assemble into pH-dependent nanostructures

Soft Matter ◽  
2021 ◽  
Vol 17 (11) ◽  
pp. 3096-3104
Author(s):  
Valeria Castelletto ◽  
Jani Seitsonen ◽  
Janne Ruokolainen ◽  
Ian W. Hamley
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Small Angle ◽  
Self Assembly ◽  
X Ray ◽  
Cryogenic Transmission Electron Microscopy ◽  
X Ray Scattering ◽  
Transmission Electron ◽  
Ph Dependent ◽  
Ray Scattering

A designed surfactant-like peptide is shown, using a combination of cryogenic-transmission electron microscopy and small-angle X-ray scattering, to have remarkable pH-dependent self-assembly properties.

scholarly journals Controlling water evaporation through self-assembly

2016 ◽  
Vol 113 (37) ◽  
pp. 10275-10280 ◽  
Author(s):  
Kevin Roger ◽  
Marianne Liebi ◽  
Jimmy Heimdal ◽  
Quoc Dat Pham ◽  
Emma Sparr
Keyword(s):  
Self Assembly ◽  
Feedback Loop ◽  
Ambient Air ◽  
Underlying Mechanism ◽  
Water Evaporation ◽  
Air Humidity ◽  
X Ray ◽  
X Ray Scattering ◽  
Composition And Structure ◽  
Living Organisms

Water evaporation concerns all land-living organisms, as ambient air is dryer than their corresponding equilibrium humidity. Contrarily to plants, mammals are covered with a skin that not only hinders evaporation but also maintains its rate at a nearly constant value, independently of air humidity. Here, we show that simple amphiphiles/water systems reproduce this behavior, which suggests a common underlying mechanism originating from responding self-assembly structures. The composition and structure gradients arising from the evaporation process were characterized using optical microscopy, infrared microscopy, and small-angle X-ray scattering. We observed a thin and dry outer phase that responds to changes in air humidity by increasing its thickness as the air becomes dryer, which decreases its permeability to water, thus counterbalancing the increase in the evaporation driving force. This thin and dry outer phase therefore shields the systems from humidity variations. Such a feedback loop achieves a homeostatic regulation of water evaporation.

scholarly journals Exploring the in meso crystallization mechanism by characterizing the lipid mesophase microenvironment during the growth of single transmembrane α-helical peptide crystals

2016 ◽  
Vol 374 (2072) ◽  
pp. 20150125 ◽  
Author(s):  
Leonie van 't Hag ◽  
Konstantin Knoblich ◽  
Shane A. Seabrook ◽  
Nigel M. Kirby ◽  
Stephen T. Mudie ◽  
...  
Keyword(s):  
Crystal Growth ◽  
Self Assembly ◽  
Lamellar Phase ◽  
Cubic Phase ◽  
Supporting Evidence ◽  
X Ray ◽  
X Ray Scattering ◽  
Standard Procedures ◽  
Helical Peptide ◽  
Saxs Analysis

The proposed mechanism for in meso crystallization of transmembrane proteins suggests that a protein or peptide is initially uniformly dispersed in the lipid self-assembly cubic phase but that crystals grow from a local lamellar phase, which acts as a conduit between the crystal and the bulk cubic phase. However, there is very limited experimental evidence for this theory. We have developed protocols to investigate the lipid mesophase microenvironment during crystal growth using standard procedures readily available in crystallography laboratories. This technique was used to characterize the microenvironment during crystal growth of the DAP12-TM peptide using synchrotron small angle X-ray scattering (SAXS) with a micro-sized X-ray beam. Crystal growth was found to occur from the gyroid cubic mesophase. For one in four crystals, a highly oriented local lamellar phase was observed, providing supporting evidence for the proposed mechanism for in meso crystallization. A new observation of this study was that we can differentiate diffraction peaks from crystals grown in meso , from peaks originating from the surrounding lipid matrix, potentially opening up the possibility of high-throughput SAXS analysis of in meso grown crystals. This article is part of the themed issue ‘Soft interfacial materials: from fundamentals to formulation’.

A multi-length-scale USAXS/SAXS facility: 10–50 keV small-angle X-ray scattering instrument

2013 ◽  
Vol 46 (5) ◽  
pp. 1508-1512 ◽  
Author(s):  
Byron Freelon ◽  
Kamlesh Suthar ◽  
Jan Ilavsky
Keyword(s):  
Small Angle ◽  
Soft Matter ◽  
High Energy ◽  
X Rays ◽  
X Ray ◽  
X Ray Scattering ◽  
Wide Range ◽  
And Performance ◽  
New Facility ◽  
Ray Scattering

Coupling small-angle X-ray scattering (SAXS) and ultra-small-angle X-ray scattering (USAXS) provides a powerful system of techniques for determining the structural organization of nanostructured materials that exhibit a wide range of characteristic length scales. A new facility that combines high-energy (HE) SAXS and USAXS has been developed at the Advanced Photon Source (APS). The application of X-rays across a range of energies, from 10 to 50 keV, offers opportunities to probe structural behavior at the nano- and microscale. An X-ray setup that can characterize both soft matter or hard matter and high-Zsamples in the solid or solution forms is described. Recent upgrades to the Sector 15ID beamline allow an extension of the X-ray energy range and improved beam intensity. The function and performance of the dedicated USAXS/HE-SAXS ChemMatCARS-APS facility is described.

scholarly journals From atoms to electrodes: Mesoscale effects in electrochemical conversion

2014 ◽  
Vol 70 (a1) ◽  
pp. C1173-C1173
Author(s):  
Kamila Wiaderek ◽  
Olaf Borkiewicz ◽  
Nathalie Pereira ◽  
Jan Ilavsky ◽  
Glenn Amatucci ◽  
...  
Keyword(s):  
Metallic Iron ◽  
Composite Electrodes ◽  
Iron Compounds ◽  
X Ray ◽  
Electrochemical Conversion ◽  
X Ray Scattering ◽  
Multiple Length Scales ◽  
Nanoscale Structure ◽  
And Performance ◽  
Identical Product

Batteries are complex multicomponent devices wherein mesoscale phenomena–the nanoscale structure and chemistry of different components, and interactions thereof–drive functionality and performance. For example, electron/ion transport within the composite electrodes relies on bi-continuous nanostructuring to form electrically and ionicly conductive paths. Electrochemical conversion of different salts of a given metal yields a common and ostensibly identical product: the zero valent metal. For example, maximal lithiation of iron-based electrodes produces metallic iron nanoparticles for oxide, fluoride, and oxyfluoride electrodes alike. Accordingly, these provide an opportunity to explore the coupling of nanostructure development and anion chemistry, and correlate these with electrochemical performance. We combine synchrotron-based small angle X-ray scattering (SAXS) and pair distribution function (PDF) measurements to probe metallic iron formed by electrochemical conversion of different iron compounds across multiple length-scales and decouple the influence of anion chemistry and reaction temperature on the atomic structure and nanoscale morphology.

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