scholarly journals Study on the Microstructure of Polyether Ether Ketone Films Irradiated with 170 keV Protons by Grazing Incidence Small Angle X-ray Scattering (GISAXS) Technology

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2717
Author(s):  
Hongxia Li ◽  
Jianqun Yang ◽  
Feng Tian ◽  
Xingji Li ◽  
Shangli Dong
Keyword(s):  
Structural Information ◽  
Absorbed Dose ◽  
Grazing Incidence ◽  
Scanning Calorimetry ◽  
Paramagnetic Resonance ◽  
X Ray Scattering ◽  
Atomic Force ◽  
Polyether Ether Ketone ◽  
Ether Ketone ◽  
Electron Paramagnetic

Polyether ether ketone (PEEK) films irradiated with 170 keV protons were calculated by the stopping and ranges of ions in matter (SRIM) software. The results showed that the damage caused by 170 keV protons was only several microns of the PEEK surface, and the ionization absorbed dose and displacement absorbed dose were calculated. The surface morphology and roughness of PEEK after proton irradiation were studied by atomic force microscope (AFM). GISAXS was used to analyze the surface structural information of the pristine and irradiated PEEK. The experimental results showed that near the surface of the pristine and irradiated PEEK exists a peak, and the peak gradually disappeared with the increasing of the angles of incidence and the peak changed after irradiation, which implies the 170 keV protons have an effect on PEEK structure. The influences of PEEK irradiated with protons on the melting temperature and crystallization temperature was investigated by differential scanning calorimetry (DSC). The DSC results showed that the crystallinity of the polymer after irradiation decreased. The structure and content of free radicals of pristine and irradiated PEEK were studied by Fourier transform infrared spectroscopy (FTIR) and electron paramagnetic resonance (EPR). The stress and strain test results showed that the yield strength of the PEEK irradiated with 5 × 1015 p/cm2 and 1 × 1016 p/cm2 was higher than the pristine, but the elongation at break of the PEEK irradiated with 5 × 1015 p/cm2 and 1 × 1016 p/cm2 decreased obviously.

An instrument for time-resolved and anomalous simultaneous small- and wide-angle X-ray scattering (SWAXS) at NSRRC

2006 ◽  
Vol 39 (6) ◽  
pp. 871-877 ◽  
Author(s):  
Ying-Huang Lai ◽  
Ya-Sen Sun ◽  
U-Ser Jeng ◽  
Jhih-Min Lin ◽  
Tsang-Lang Lin ◽  
...  
Keyword(s):  
Lipid Membrane ◽  
Quantum Wires ◽  
Grazing Incidence ◽  
Anomalous Scattering ◽  
Wide Angle ◽  
Scanning Calorimetry ◽  
Time Resolved ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

A SWAXS (small- and wide-angle X-ray scattering) instrument was recently installed at the wiggler beamline BL17B3 of the National Synchrotron Radiation Research Center (NSRRC), Taiwan. The instrument, which is designed for studies of static and dynamic nanostructures and correlations between the nano (ormeso) structure (SAXS) and crystalline structure (WAXS), provides a flux of 1010–1011photon s−1at the sample at energies between 5 and 14 keV. With a SAXS area detector and a WAXS linear detector connected to two data acquisition systems operated in master–slave mode, the instrument allows one to perform time-resolved as well as anomalous scattering measurements. Data reduction algorithms have been developed for rapid processing of the large SWAXS data sets collected during time-resolved measurements. The performance of the instrument is illustrated by examples taken from different classes of ongoing projects: (i) time-resolved SAXS/WAXS/differential scanning calorimetry (DSC) with a time resolution of 10 s on a semicrystalline poly(hexamethylene terephthalate) sample, (ii) anomalous SAXS/WAXS measurements on a nanoparticulate PtRu catalyst, and (iii) grazing-incidence SAXS of a monolayer of oriented semiconductor quantum wires, and humidity-controlled ordering of Alamethicin peptides embedded in an oriented lipid membrane.

When dendrimers are not better – rational design of nanolayers for high-performance organic electronic devices

Nanoscale ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 4463-4470 ◽  
Author(s):  
Maxim A. Shcherbina ◽  
Oleg V. Borshchev ◽  
Alexandra P. Pleshkova ◽  
Sergei A. Ponomarenko ◽  
Sergei N. Chvalun
Keyword(s):  
High Performance ◽  
Rational Design ◽  
Electronic Devices ◽  
Carbosilane Dendrimers ◽  
Scanning Calorimetry ◽  
Organic Electronic Devices ◽  
X Ray ◽  
Force Microscopy ◽  
X Ray Scattering ◽  
Atomic Force

Several generations of carbosilane dendrimers with quaterthiophene end groups were studied by X-ray scattering, differential scanning calorimetry, polarizing optical and atomic force microscopy and molecular modelling.

The electron paramagnetic resonance of methylene

1984 ◽  
Vol 62 (12) ◽  
pp. 1724-1730 ◽  
Author(s):  
R. A. Bernheim
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Bond Angle ◽  
Structural Information ◽  
Zero Field ◽  
Paramagnetic Resonance ◽  
Structure Splitting ◽  
Parameters Measurement ◽  
Laser Magnetic Resonance ◽  
Electron Paramagnetic ◽  
Electronic Ground

The electron paramagnetic resonance studies of methylene arc reviewed. The structural information that resulted include verification of the triplet multiplicity of the electronic ground state, the discovery of a bent geometry for the molecule with a bond angle of 134°, measurement of the zero-field or fine-structure splitting parameters, measurement of the g-factor tensor, and measurement of the isotropic and anisotropic 13C hyperfine interaction. The results are compared with recent measurements obtained with laser magnetic resonance techniques and theoretical treatments.

scholarly journals A new building block for DNA network formation by self-assembly and polymerase chain reaction

2014 ◽  
Vol 10 ◽  
pp. 1037-1046 ◽  
Author(s):  
Holger Bußkamp ◽  
Sascha Keller ◽  
Marta Robotta ◽  
Malte Drescher ◽  
Andreas Marx
Keyword(s):  
Self Assembly ◽  
Building Block ◽  
Network Formation ◽  
Electron Paramagnetic Resonance Spectroscopy ◽  
Resonance Spectroscopy ◽  
Paramagnetic Resonance ◽  
Force Microscopy ◽  
Atomic Force ◽  
Polymerase Chain ◽  
Electron Paramagnetic

The predictability of DNA self-assembly is exploited in many nanotechnological approaches. Inspired by naturally existing self-assembled DNA architectures, branched DNA has been developed that allows self-assembly to predesigned architectures with dimensions on the nanometer scale. DNA is an attractive material for generation of nanostructures due to a plethora of enzymes which modify DNA with high accuracy, providing a toolbox for many different manipulations to construct nanometer scaled objects. We present a straightforward synthesis of a rigid DNA branching building block successfully used for the generation of DNA networks by self-assembly and network formation by enzymatic DNA synthesis. The Y-shaped 3-armed DNA construct, bearing 3 primer strands is accepted by Taq DNA polymerase. The enzyme uses each arm as primer strand and incorporates the branched construct into large assemblies during PCR. The networks were investigated by agarose gel electrophoresis, atomic force microscopy, dynamic light scattering, and electron paramagnetic resonance spectroscopy. The findings indicate that rather rigid DNA networks were formed. This presents a new bottom-up approach for DNA material formation and might find applications like in the generation of functional hydrogels.

scholarly journals Thin-film morphologies of block copolymers with nanoparticles

2015 ◽  
Vol 30 (S1) ◽  
pp. S16-S24 ◽  
Author(s):  
Dieter Jehnichen ◽  
Doris Pospiech ◽  
Peter Friedel ◽  
Guping He ◽  
Alessandro Sepe ◽  
...  
Keyword(s):  
Thin Films ◽  
Diblock Copolymers ◽  
Grazing Incidence ◽  
Polymer Surfaces ◽  
Nanostructured Surfaces ◽  
Force Microscopy ◽  
Molar Ratios ◽  
X Ray Scattering ◽  
Atomic Force

Diblock copolymers (BCPs) show phase separation on mesoscopic length scales and form ordered morphologies in both bulk and thin films, the latter resulting in nanostructured surfaces. Morphologies in thin films are strongly influenced by film parameters, the ratio of film thickness and bulk domain spacing. Laterally structured polymer surfaces may serve as templates for controlled assembly of nanoparticles (NPs). We investigated the BCP of poly(n-pentyl methacrylate) and poly(methyl methacrylate) which show bulk morphologies of stacked lamellae or hexagonally packed cylinders. Thin films were investigated by atomic force microscopy and grazing-incidence small-angle X-ray scattering. For film thicknesses f well below dbulk, standing cylinder morphologies were observed in appropriate molar ratios, while film thicknesses around and larger than dbulk resulted in cylinders arranged parallel to surface. To alter and/or improve the morphology also in presence of different NPs (e.g., silica, gold), solvent vapour annealing (SVA) was applied. The BCP morphology usually remains unchanged but periodicities change depending on type and amount of incorporated NPs. It was found that silica clusters enlarge lateral distances of cylinders, whereas Au NPs reduce it. The effect of SVA is weak. The quality of morphology is slightly improved by SVA and lateral distances remain constant or are slightly reduced.

Relationship Between Spectroscopic and Structural Properties of Poly(meta/para Phenylene)

1999 ◽  
Vol 598 ◽  
Author(s):  
Cherif. Dridi ◽  
Joël. Davenas ◽  
Ahmed. Touhami ◽  
Hafedh. Ben Ouada ◽  
Hassen. Mâaref ◽  
...  
Keyword(s):  
Conjugated Polymer ◽  
Quantum Confinement ◽  
Blue Shift ◽  
Film Morphology ◽  
Energy Band Gap ◽  
Paramagnetic Resonance ◽  
Force Microscopy ◽  
Atomic Force ◽  
Electron Paramagnetic ◽  
Insight Into

ABSTRACTWe have used electron paramagnetic resonance (EPR) spectroscopy for investigating the properties of spins, such as those carried by polarons which carry both spin and charge in an electrosynthesized poly (meta/para phenylene) PMPP.Indeed, the study of their mobility provides an insight into the charge transport properties of the conjugated polymer in a microscopic scale.Moreover, we report a correlation between thin film morphology, chainlength and optical gap.Particularly, we show a blue shift upon decreasing chainlength. Furthermore, we have observed a blue shift of the energy band gap with the decrease of the surface grain size deduced from atomic force microscopy (AFM) analyses. This result has been explained in terms of quantum confinement.

scholarly journals The molecular mechanism of Hsp90-induced oligomerization of Tau

2019 ◽  
Author(s):  
Sabrina Weickert ◽  
Magdalena Wawrzyniuk ◽  
Laura John ◽  
Stefan G. D. Rüdiger ◽  
Malte Drescher
Keyword(s):  
Structural Information ◽  
Conformational Ensemble ◽  
Toxic Agent ◽  
Paramagnetic Resonance ◽  
Biologically Relevant ◽  
Intrinsically Disordered ◽  
Tau Oligomers ◽  
Paper Clip ◽  
Repeat Domain ◽  
Electron Paramagnetic

AbstractAggregation of the microtubule-associated protein Tau is a hallmark of Alzheimer’s disease with Tau oligomers suspected as the most toxic agent. Tau is a client of Hsp90, though it is unclear whether and how the chaperone massages the structure of intrinsically disordered Tau. Using electron paramagnetic resonance, we extract structural information from the very broad conformational ensemble of Tau: Tau in solution is highly dynamic and polymorphic, though ‘paper-clip’-shaped by long-range contacts. Interaction with Hsp90 promotes an open Tau conformation, which we identify as the molecular basis for the formation of small Tau oligomers by exposure of the aggregation-prone repeat domain to other Tau molecules. At the same time, formation of Tau fibrils is inhibited. We therefore provide the nanometer-scale zoom into chaperoning an amyloid client, highlighting formation of oligomers as the consequence of this biologically relevant interaction.

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