scholarly journals Contrast Variation Small Angle Neutron Scattering by Dynamic Nuclear Polarization: A Case of Time-of-Flight Method in J-PARC

hamon ◽  
2015 ◽  
Vol 25 (3) ◽  
pp. 214-221
Author(s):  
Yohei Noda ◽  
Satoshi Koizumi ◽  
Tomomi Masui ◽  
Ryo Mashita ◽  
Hiroyuki Kishimoto ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Dynamic Nuclear Polarization ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Nuclear Polarization ◽  
Time Of Flight ◽  
Contrast Variation ◽  
Time Of Flight Method

scholarly journals Contrast variation by dynamic nuclear polarization and time-of-flight small-angle neutron scattering. I. Application to industrial multi-component nanocomposites

2016 ◽  
Vol 49 (6) ◽  
pp. 2036-2045 ◽  
Author(s):  
Yohei Noda ◽  
Satoshi Koizumi ◽  
Tomomi Masui ◽  
Ryo Mashita ◽  
Hiroyuki Kishimoto ◽  
...  
Keyword(s):  
Form Factor ◽  
Binary Mixture ◽  
Neutron Scattering ◽  
Dynamic Nuclear Polarization ◽  
Small Angle ◽  
Ternary Mixture ◽  
Small Angle Neutron Scattering ◽  
Nuclear Polarization ◽  
Scattering Function ◽  
Contrast Variation

Dynamic nuclear polarization (DNP) at low temperature (1.2 K) and high magnetic field (3.3 T) was applied to a contrast variation study in small-angle neutron scattering (SANS) focusing on industrial rubber materials. By varying the scattering contrast by DNP, time-of-flight SANS profiles were obtained at the pulsed neutron source of the Japan Proton Accelerator Research Complex (J-PARC). The concentration of a small organic molecule, (2,2,6,6-tetramethylpiperidine-1-yl)oxy (TEMPO), was carefully controlled by a doping method using vapour sorption into the rubber specimens. With the assistance of microwave irradiation (94 GHz), almost full polarization of the paramagnetic electronic spin of TEMPO was transferred to the spin state of hydrogen (protons) in the rubber materials to obtain a high proton spin polarization (PH). The following samples were prepared: (i) a binary mixture of styrene–butadiene random copolymer (SBR) with silica particles (SBR/SP); and (ii) a ternary mixture of SBR with silica and carbon black particles (SBR/SP/CP). For the binary mixture (SBR/SP), the intensity of SANS significantly increased or decreased while keeping itsqdependence forPH= −35% orPH= 40%, respectively. Theqbehaviour of SANS for the SBR/SP mixture can be reproduced using the form factor of a spherical particle. The intensity at lowq(∼0.01 Å−1) varied as a quadratic function ofPHand indicated a minimum value atPH= 30%, which can be explained by the scattering contrast between SP and SBR. The scattering intensity at highq(∼0.3 Å−1) decreased with increasingPH, which is attributed to the incoherent scattering from hydrogen. For the ternary mixture (SBR/SP/CP), theqbehaviour of SANS was varied by changingPH. AtPH= −35%, the scattering maxima originating from the form factor of SP prevailed, whereas atPH= 29% andPH= 38%, the scattering maxima disappeared. After decomposition of the total SANS according to inverse matrix calculations, the partial scattering functions were obtained. The partial scattering function obtained for SP was well reproduced by a spherical form factor and matched the SANS profile for the SBR/SP mixture. The partial scattering function for CP exhibited surface fractal behaviour according toq−3.6, which is consistent with the results for the SBR/CP mixture.

Inhomogeneous dynamic nuclear polarization of protons in a lamella-forming diblock copolymer investigated by a small-angle neutron scattering method

2011 ◽  
Vol 44 (3) ◽  
pp. 503-513 ◽  
Author(s):  
Yohei Noda ◽  
Takayuki Kumada ◽  
Takeji Hashimoto ◽  
Satoshi Koizumi
Keyword(s):  
Neutron Scattering ◽  
Diblock Copolymer ◽  
Dynamic Nuclear Polarization ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Nuclear Polarization ◽  
Spin Diffusion ◽  
Second Order ◽  
Third Order ◽  
Proton Polarization

By combining two methods of selective doping of paramagnetic species into a microdomain and small-angle neutron scattering (SANS), thespatially inhomogeneous proton polarizationcreated by dynamic nuclear polarization (DNP) has been precisely evaluated. A lamella-forming diblock copolymer composed of polystyrene (PS) and polyisoprene (PI) block chains (PS-b-PI) was employed, the SANS profile of which clearly shows scattering peaks up to the third order due to interlamellar interference. As a source of electron spin for DNP, 2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO) was doped into one or other of the microdomains; samples with PS or PI microdomains selectively doped with TEMPO are designated PS.-b-PI and PS-b-PI., respectively. The SANS intensity at the first- and third-order peaks is well reproduced by assuming that the proton polarization is homogeneous throughout the sample, but that at the second-order peak cannot be explained by this assumption. This anomaly regarding the second-order peak was successfully explained by a model postulating that proton polarization in a doped microdomain decreases with increasing distance from the interface with a neighbouring doped microdomain. The decrease in proton polarization at the centre of a doped microdomain was estimated to be 0.07 (2) for PS-b-PI.and 0.05 (1) for PS.-b-PI, relative to constant proton polarization in a doped microdomain. The inhomogeneous proton polarization results from two competing dynamic processes,i.e.spin diffusion from doped to undoped microdomains, and spin lattice relaxation occurring on the pathway of proton spin diffusion.

scholarly journals Development of closed -cycle dynamic nuclear polarization system for small -angle neutron scattering and neutron reflectometry

2018 ◽  
Author(s):  
Takayuki Kumada ◽  
Kazuhiro Akutsu ◽  
Kazuki Ohishi ◽  
Yukihiko Kawamura ◽  
Toshiaki Morikawa ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Dynamic Nuclear Polarization ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Nuclear Polarization ◽  
Neutron Reflectometry ◽  
Closed Cycle

scholarly journals Creating local contrast in small-angle neutron scattering by dynamic nuclear polarization

2007 ◽  
Vol 40 (s1) ◽  
pp. s106-s110 ◽  
Author(s):  
B. van den Brandt ◽  
H. Glättli ◽  
P. Hautle ◽  
J. Kohlbrecher ◽  
J. A. Konter ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Dynamic Nuclear Polarization ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Nuclear Polarization ◽  
Local Contrast

Ultra-Small-Angle Neutron Scattering Study of Colloidal Alloys. 1. Contrast Variation Experiments for Mixtures of Hydrogenated and Deuterated Polystyrene Latices in H2O/D2O

Langmuir ◽  
1999 ◽  
Vol 15 (2) ◽  
pp. 293-296 ◽  
Author(s):  
Hideki Matsuoka ◽  
Takashi Ikeda ◽  
Hitoshi Yamaoka ◽  
Mitsuhiro Hashimoto ◽  
Toshio Takahashi ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Contrast Variation ◽  
Scattering Study ◽  
Neutron Scattering Study

Mechanically Interlocked Structure of Polyrotaxane Investigated by Contrast Variation Small-Angle Neutron Scattering

2009 ◽  
Vol 42 (16) ◽  
pp. 6327-6329 ◽  
Author(s):  
Koichi Mayumi ◽  
Hitoshi Endo ◽  
Noboru Osaka ◽  
Hideaki Yokoyama ◽  
Michihiro Nagao ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Contrast Variation

Small angle neutron scattering experiments on nanostructured matter using contrast variation

1997 ◽  
Vol 9 (1-8) ◽  
pp. 327-330
Author(s):  
S. Janßen ◽  
J. Wagner ◽  
H. Natter ◽  
J. Prewo ◽  
R. Rupp ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Contrast Variation

Structure of Nanocomposite Hydrogel Investigated by Means of Contrast Variation Small-Angle Neutron Scattering

2008 ◽  
Vol 41 (14) ◽  
pp. 5406-5411 ◽  
Author(s):  
Hitoshi Endo ◽  
Sho Miyazaki ◽  
Kazutoshi Haraguchi ◽  
Mitsuhiro Shibayama
Keyword(s):  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Nanocomposite Hydrogel ◽  
Contrast Variation

scholarly journals Amphiphilic Comb Polymers as New Additives in Bicontinuous Microemulsions

Nanomaterials ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2410
Author(s):  
Debasish Saha ◽  
Karthik R. Peddireddy ◽  
Jürgen Allgaier ◽  
Wei Zhang ◽  
Simona Maccarrone ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Amphiphilic Polymers ◽  
Side Chain ◽  
Side Chains ◽  
Contrast Variation ◽  
Dna Complexes ◽  
Comb Polymers ◽  
Polymer Architectures

It has been shown that the thermodynamics of bicontinuous microemulsions can be tailored via the addition of various different amphiphilic polymers. In this manuscript, we now focus on comb-type polymers consisting of hydrophobic backbones and hydrophilic side chains. The distinct philicity of the backbone and side chains leads to a well-defined segregation into the oil and water domains respectively, as confirmed by contrast variation small-angle neutron scattering experiments. This polymer–microemulsion structure leads to well-described conformational entropies of the polymer fragments (backbone and side chains) that exert pressure on the membrane, which influences the thermodynamics of the overall microemulsion. In the context of the different polymer architectures that have been studied by our group with regards to their phase diagrams and small-angle neutron scattering, the microemulsion thermodynamics of comb polymers can be described in terms of a superposition of the backbone and side chain fragments. The denser or longer the side chain, the stronger the grafting and the more visible the brush effect of the side chains becomes. Possible applications of the comb polymers as switchable additives are discussed. Finally, a balanced philicity of polymers also motivates transmembrane migration in biological systems of the polymers themselves or of polymer–DNA complexes.

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