The conduction reduction of proton exchange membranes (PEMs) under low-humidity conditions is one of the most severe problems, leading to significance performance loss in conventional fuel cells. Recently, we identified that radiation-grafted PEMs possess excellent conductivity under high-temperature and low-humidity conditions, compared with the benchmark material Nafion. In this study, we aim to gain a deep understanding of water transport in graft-type PEMs, which is the dominant factor for conductivity, by taking into account two distinctive parameters: water dynamics and ion-channel structural tortuosity. Especially, water dynamics are distinctly detected using quasielastic neutron scattering (QENS), together with the ion-channel structure using small-angle neutron scattering, owing to the newly prepared deuterated polystyrene sulfonic acid grafting onto a fully fluorinated base polymer, which minimizes the incoherent scattering from polymers. The QENS results show three types of water molecules within the ion-conducting channels in PEMs: immobile water tightly bound to ionic groups and two diffusive water molecules, slow and fast, near and relatively far from ionic groups, respectively. There exists a threshold hydration number (lambda w,thre) for the onset of proton conductivity, above which long-range water transport may occur. Below lambda w,thre, slow and fast water motions are characterized by two independent confined-sphere diffusion models (CSDM), while above lambda w,thre, the slow and fast water motions follow jump diffusion and CSDM, respectively. We further propose the ratio of local to macroscopic water diffusivities (R t) as a measure relevant to the local-to-bulk structural tortuosity, which is as high as similar to 137 below lambda w,thre, revealing the prohibition of long-range water transport, in contrast to the notably low R t values above lambda w,thre that are observed in both graft-type PEMs and Nafion, suggesting similar structural tortuosity for water transport.

We have elucidated the polymer adsorption layer structure in filler-rubber systems by conducting spin-contrast-variation small-angle neutron scattering (SANS) on partially and fully swollen filler-rubber samples with and without a silane coupling agent. In spin-contrast-variation SANS, dynamic nuclear polarization (DNP) was used to polarize protons and change their scattering length with respect to polarized neutron beams significantly. SANS measurements were performed in dynamically polarized states using a DNP cryostat (1.2 K and 3.35 T). From SANS profiles obtained at various proton spin polarizations, partial scattering functions (PSFs) for each component were separated by regarding each sample as a three-component system composed of silica, polymer and deuterated toluene. To analyze the obtained PSFs in detail, we built a structure model for the silica aggregates and the surrounding polymer adsorption layer. Numerical calculation based on this model successfully reproduced the experimentally obtained PSFs, providing the structural parameters of the silica aggregates and polymer adsorption layer. The results showed a considerable difference in structural parameters between the partially and fully swollen states. For the sample with the silane coupling agent, the thickness of the polymer adsorption layer decreased as the solvent fraction increased. The difference in polymer volume fraction between the polymer adsorption layer and the outside matrix was very small in less swollen states but significant in the fully swollen state. Furthermore, the scattering contribution of the polymer chains in the solvent was accurately separated via contrast variation. In the swollen silica-filled rubber without the silane coupling agent, the size of the polymer-dense regions was almost constant, regardless of the swelling ratio. By contrast, in the swollen silica-filled rubber with the silane coupling agent, the size of the polymer-dense regions significantly increased by a factor of 2 with an increase in the swelling ratio.

According to a scheme of room-temperature transesterification [S. Tanaka et al. Green Chem. 2021, 23, 9412-9416.], a polyethylene terephthalate (PET) film was chemically decomposed, and its surface structure was inspected by using scanning electron microscopy (SEM) and X-ray grazing incidence small-angle scattering (XGSAS), covering small-angle scattering (SAXS) and diffraction (XRD). In the reaction solution mixed with dimethyl carbonate (DMC), the decomposed fragments of ethylene glycol (EG) are immediately converted to ethylene carbonate (EC) (chemical-trap effect) so the decomposition reaction continuously proceeds forward at room temperature. After 3 days of reaction, SEM elucidated that the amorphous regions are dominantly degraded, and stripes of crystalline bundles remain on the film surface. The degraded fragments, i.e., dimethyl terephthalate (DMT) monomer or its oligomers, immediately form the cauliflower-like granule (600 nm in diameter) composed of primary clusters (40 nm in diameter), which are connected in a line and emanate from a core of the granule (referred to as the "Pot & Sugar" structure). Thus, DMT cannot be backward polymerized again (physical trap effect). In an in situ or ex situ manner, X-rays irradiated at a grazing angle to the film surface elucidated that the crystallinity at the film surface apparently increases, and small-angle scattering originating from the primary clusters of DMT appears on the surface. Although methanol, a key reagent, is a poor solvent for PET, it diffuses into the amorphous region on the film surface and more easily from the edge surface than the film surface. The swelling behavior at the film surface was accelerated by decomposition (reaction absorption).

The nano-sized graphene with a petaland seed-like structure may induce neutron coherent scattering. We have studied a possible effect according to which the increase of the number of graphene seed-like structures produces an enhancement of the coherent scattering. To evaluate this, we focused on Raman spectra that characterize the stacking structure, crystal irregularities, and defects promoted by graphene growth. By focusing on this information, we tried to find parameters related to the nano-sized structure of graphene, and explored whether they can be related to the coherent scattering. As a result, it is suggested that the increase of the G/D ratio and the decrease of the G/2D ratio in the Raman spectra correlate strongly with the increase of the coherent scattering.

To elucidate the complexity of cross-linking in multinetwork elastomers (MNEs), we employed small-angle neutron scattering combined with dynamic nuclear polarization (DNP-SANS). MNEs were designed as thermoplastic elastomers with three kinds of cross-linking consisting of hydrogen, covalent, and clay plane bonds. DNP-SANS profiles were obtained with continuously changing scattering contrasts for MNEs with different cross-link densities. We clearly recognize the three matching points in scattering intensity, originating from pairs of cross-linking groups, clay, or main chains. DNP-SANS profiles were decomposed into three partial scattering functions for self-terms of cross-linking groups clay and their cross-terms. The self-term exhibits a scattering maximum due to the interplane distance of clay, which changes with the cross-link density. The cross-term between clay and cross-link was obtained as negative, indicating that the cross-linking domains are tightly correlated, localizing on the clay surface. The results indicate that DNP-SANS is a crucial technique for obtaining structural details of MNE cross-linking without chemical deuteration.

To enhance the intensity of neutron beams, attention has been focused on the coherent scattering caused by nano-sized particle ensembles, and the use of nano-diamonds has been actively considered. Graphene, which has an sp2 carbon crystal structure, has a larger van der Waals force compared to sp3 carbon crystal structure such as nano-diamonds. Additionally, the bonding force between carbon atoms in graphene is strong, which makes it easier to mold into a large block and plate and to adapt to higher radiation fields. However, graphene is easily to cause aggregation due to its large van der Waals force, making it difficult to form a nano-sized three-dimensional structure. To address this problem, we focused on the hot isostatic pressing (HIP) method, which uses resin powder as the raw material and produces vapor-phase-grown graphene through HIP treatment. We have reported a method for producing free-standing, three-dimensional graphene called "graphene flower" made of nanosized graphene and a method for controlling the nano-size of graphene. Additionally, we presented a prototype of a graphene neutron reflector and measured the coherent scattering of neutrons by graphene for the first time. In this paper, we will report on the optimization of the graphene manufacturing method using the HIP process to improve the coherent scattering performance of neutrons.

We report the construction and performance of the small-angle neutron scattering instrument ib-SAS at the compact accelerator-based neutron source RANS, RIKEN, Wako, Japan. With this instrument, we aim to increase the opportunities for using neutrons for university education and/or industrial use (e.g. screening for inferior goods). A time-of-flight method, combined with pulsed neutrons with a wide wavelength band from 1 to 10 angstrom, is necessary to compensate for the weak luminescence of the compact neutron source. Further enhancement has been achieved by employing a multi-pinhole collimator as a converging-beam device; 81 (= 9 x 9) pinholes select thermal neutrons emitted from the large surface area of a solid polyethylene (PE) moderator and produce a focused beam on the detector. To reduce the background originating from stray neutrons in the beam hall of RANS, we keep the path of small-angle scattering in a vacuum and cover it by a thick shield of Cd plates and PE blocks containing B4C powder. To cover a wide range of length scales d [or wavenumber q (= 2 pi/d)], three detector blocks (small-angle, wide-angle and backward scattering) were installed on the ib-SAS instrument. The small-angle scattering obtained for glassy carbon and sodium dodecyl sulfate micelle solutions is quantitatively compared with that obtained from the iMATERIA instrument (BL20) at J-PARC, Tokai, with respect to the covered q range and the measurement efficiency and statistics. Similarly to scanning electron microscopy, the SANS instrument at RANS was used to provide a map image showing the water distribution in a mortar plate, the bottom of which was immersed in water. The incoherent scattering from hydrogen was determined and plotted as a function of height.

The partial scattering function (PSF) analysis through contrast variation small-angle neutron scattering experiments is applied to characterize structures of anion-exchange membranes (AEMs), prepared by graft copolymerization of 2-methyl-N-vinylimidazolium (Im) and styrene (St) monomers with Im/St ratios of 62/38 and 26/74 (denoted as AEM_IS64 and AEM_IS37, respectively), on a poly(ethylene-co-tetrafluoroethylene) base polymer (BP). The PSF self-terms can be expressed by the combination of mass fractal, Teubner-Strey, Guinier exponential, and hard-sphere structural models to give exact structural information such as shape and size of individual domains of hydrophobic BP, hydrophilic graft-polymer (GP), and water (W). For AEM_IS64, the hydrophilic ion channels (GP/W domains) show bicontinuous and spherical structures with mean separation distances of 33-34 nm and a radius of 4.0 nm, respectively. This result suggests a new structural feature of the coexistence of bicontinuous and isolated GP/W spheres. Furthermore, in a low q-region, a slightly larger fractal dimension for GP (similar to 1.7) than those of BP and W (similar to 1.1) strongly supports the previously proposed "conducting and nonconducting two-phase structure" because only GP distributes in both phases. In AEM_IS37, GP/W and BP domains show an ion channel network structure with random particles having an average radius of gyration of 10.0 nm, and hard-sphere model fitting in the high-q region confirms previously proposed "waterpuddle" structure with 3.8 nm diameter. PSF analysis in this work visualized the entire hierarchical structure of individual components in graft-type AEMs, providing mechanistic insights into the effects of functional GPs on phase-separation and ion channel structures.

We have been developing nanosized graphene, called graphene flower, as a material that induces coherent scattering very cold neutrons. Previous experiments have found that the seed part of the graphene flower is more effective than the petal part in increasing the coherent scattering. Based on these results, we found that further modification of the graphene flower to increase the seed portion increased the total cross-section, although it did not reach the level of nanodiamonds.

It is proposed that nanosized graphene aggregation could facilitate coherent neutron scattering under particle size conditions similar to nanodiamonds to enhance neutron intensity below cold neutrons. Using the RIKEN accelerator-driven compact neutron source and iMATERIA at J-PARC, we performed neutron measurement experiments, total neutron cross-section and small-angle neutron scattering on nanosized graphene aggregation. For the first time, the measured data revealed that nanosized graphene aggregation increased the total neutron cross-sections and small-angle scattering in the cold neutron energy region. This is most likely due to coherent scattering, resulting in higher neutron intensities, similar to nanodiamonds.

Dynamic nuclear polarization (DNP) is effective for controlling the neutron scattering length of protons and can be utilized for contrast variation in small-angle neutron scattering (SANS). Using the TEMPOL solution soaking method as electron spin doping, the DNP–SANS technique was applied to human hair fiber for the first time. For dry and D 2 O-swollen hair samples, a drastic change in the SANS profile was observed at high polarization conditions (| P H P N | ∼ 60%, where P H and P N are the proton and neutron spin polarization, respectively). The SANS profile as a function of the magnitude of the scattering vector, q , was composed of a low- q upturn, a middle- q oscillation and a high- q flat region. The low- q upturn was assumed to be a combination of two power-law functions, q −4 due to a large structure interface (Porod's law) and q −2 due to random coil. The middle- q oscillation was well reproduced by numerical calculation based on the structure model of intermediate filaments (IFs) as proposed by Er Rafik et al. [ Biophys. J. (2004), 86 , 3893–3904]: one pair of keratin coiled-coils is located at the center and surrounded by seven pairs of keratin coiled-coils located in a circle (called the `7 + 1' model), and a collection of IFs is arranged in a quasi-hexagonal manner. For the observed SANS profiles for different P H P N , the IF term contribution maintained a constant q -dependent profile, despite significant changes in intensity. This indicates that the macrofibril is composed of two domains (keratin coiled-coils and matrix). In addition, D 2 O swelling enhanced the IF term intensity and shifted the polarization-dependent local minimum to higher P H P N . This behavior was reproduced by contrast factor calculation based on the two-domain model. Scattering length densities of keratin coiled-coil and surrounding matrix domains were calculated by use of the known amino acid composition, considering the hydrogen–deuterium exchange reaction during soaking with D 2 O solution of TEMPOL. As a result, it was found that for keratin coiled-coil domains, about 40% of the peptide backbone amide NH protons were replaced with deuterons. This means that 68% of the α-helix domain is rigid, but the rest is flexible to allow dynamic dissociation of the hydrogen bond. Furthermore, the local mass density of each domain was precisely evaluated. The obtained data are expected to be a guide for further detailed investigation of keratin and keratin-associated protein distribution. This approach is expected to be applied to a wide variety of bio-derived materials, which are water absorbing in general.

A novel surfactant of N–dodecanoyl–N–(2-hydroxyethyl)–β–alanine (coded as C12–EtOH–βAla) was synthesized by modifying the methyl group of N–dodecanoyl–N–methyl–β–alanine (coded as C12–Me–βAla). Amino-acid-type surfactants (C12–EtOH–βAla and C12–Me–βAla) are more healthy and environmentally friendly compared to sodium dodecyl sulfate (SDS). To investigate the microstructures of these new surfactants, we employed a method of time-of-flight small-angle neutron scattering (TOF SANS) at a pulsed neutron source, Tokai Japan (J–PARC). The advances in TOF SANS enable simultaneous multiscale observations without changing the detector positions, which is usually necessary for SANS at the reactor or small-angle X-ray scattering. We performed in situ and real-time observations of microstructures of collapsing shampoo foam covering over a wide range of length scales from 100 to 0.1 nm. After starting an air pump, we obtained time-resolved SANS from smaller wave number, small-angle scattering attributed to (1) a single bimolecular layer with a disk shape, (2) micelles in a bimolecular layer, and (3) incoherent scattering due to the hydrogen atoms of surfactants. The micelle in the foam film was the same size as the micelle found in the solution before foaming. The film thickness (~27 nm) was stable for a long time (<3600 s), and we simultaneously found a Newton black film of 6 nm thickness at a long time limit (~1000 s). The incoherent scattering obtained with different contrasts using protonated and deuterated water was crucial to determining the water content in the foam film, which was about 10~5 wt%.

In this work, a systematic work was performed to investigate the electrochemical transport properties of acceptor-doped BaZrO3 by measuring electromotive force on various gas concentration cells. For the measurements in the wet oxidizing atmosphere, where significant hole conduction occurs, the transport numbers of the ionic conduction were corrected by taking the effect of electrode polarization into consideration. The results revealed that regardless of whether Sc, Y, In, Ho, Er, Tm or Yb was doped, proton conduction predominated in the reducing atmosphere with the transport number close to unit. However, the contribution of ionic conduction weakens, and the contribution of hole conduction enhances, when the samples are exposed to the moist oxidizing atmosphere. In addition, introducing Ba-deficiency results in degraded electrochemical conductivity, but the transport number in either the moist reducing or the moist oxidizing atmosphere does not change obviously.

In this work, a systematic work was performed to investigate the electrochemical transport properties of acceptor-doped BaZrO3 by measuring electromotive force on various gas concentration cells. For the measurements in the wet oxidizing atmosphere, where significant hole conduction occurs, the transport numbers of the ionic conduction in the oxidizing atmosphere were corrected by taking the effect of electrode polarization into consideration. The results revealed that regardless of whether Sc, Y, In, Ho, Er, Tm or Yb was doped, proton conduction predominates in the reducing atmosphere with the transport number close to unit. However, the contribution of ionic conduction weakens, and the contribution of hole conduction enhances, when the samples are exposed to the moist oxidizing atmosphere. In addition, introducing Ba-deficiency results in degraded electrochemical conductivity, but the transport number in either the moist reducing or the moist oxidizing atmosphere does not change obviously.

It is known that damaged hair has a part of its internal structure damaged, and its water absorption and desorption behavior are different. In recent years, it has been reported that internal lipids play an important role in the adsorption and desorption of water to the hair. Therefore, we investigate whether the water distribution in hair and the amount of internal lipids are related.

Ibaraki university developed the novel neutron microscope on the instrument iMATERIA at MLF of J-PARC, which was originally a powder diffractometer, recently reinforced by detecting small-angle scattering. The method of dynamic nuclear polarization (DNP) for protons was combined with small angle neutron scattering (SANS)(DNP-SANS). In a long course of history of DNP, our activity is the world's first challenge to incorporate DNP-SANS for routine industry uses. This “neutron microscope" provides us multiple reciprocal space images by changing scattering lengths of proton, in turn by varying “contrast" of individual scattering components. Conventionally, for the contrast variation, chemical treatments are required to substitute protons with deuterons. The DNP approach is suitable for industry application (for example to observe tire rubbers), because we do not need highly-specialized deuterium substitution. In this article, we describe theoretical background of DNP including scattering functions and the experimental of 7T super-conductive magnet, NMR to evaluate proton spin polarization, and microwave to change polarization. The sample preparation to dope radicals into sample specimens are necessary. We review the studies on homopolymers of polystyrene and polyethylene, poly (styrene-b-isoprene) diblock copolymer, and vulcanized SBR rubber.

A method of time-of-flight, small-angle neutron scattering (TOF-SANS) has been developed based on the iMATERIA powder diffractometer at BL20, of the Materials and Life Sciences Facility (MLF) at the high-intensity proton accelerator (J-PARC). A large-area detector for SANS, which is composed of triple-layered 3He tube detectors, has a hole at its center in order to release a direct beam behind and to detect ultra-small-angle scattering. As a result, the pulsed-neutron TOF method enables us to perform multiscale observations covering 0.003 < q (Å−1) < 40 (qmax/qmix = 1.3 × 104) and to determine the static structure factor S(q) and/or form factor P(q) under real-time and in-situ conditions. Our challenge, using unique sample accessories of a super-conducting magnet and polarized neutron, is dynamic nuclear polarization (DNP) for contrast variation, especially for industrial use. To reinforce conventional SANS measurements with powder materials, grazing-incidence small-angle neutron scattering (GISANS) or reflectivity is also available on the iMATERIA instrument.