The time-of-flight (TOF) type near-backscattering spectrometer (n-BSS), DNA, with Si crystal analyzers was built and started operation in 2012 at the Materials Life Science Experimental Facility (MLF) of Japan Proton Accelerator Research Complex (J-PARC). DNA is first n-BSS pulse shaping chopper installed a spallation pulsed neutron source. It offers currently highest energy-resolution about 2.4 micro eV by operating double-disk 225 Hz whose phase optimized to narrowest slit 10 mm width....

J-PARC Center, Japan Atomic Energy Agency (JAEA), Tokai, Ibaraki 319-1195, Research Center for Neutron Science and Technology, Comprehensive Organization Society (CROSS), 319-1106, High Accelerator (KEK), Tsukuba, 305-0801, Reactor Institute, Kyoto University (KURRI), Kumatori, Osaka 590-0494,

Double-network hydrogels (DN-gels) prepared from the combination of a moderately cross-linked anionic polyelectrolyte (PE) and an uncross-linked linear polymer solution (NP) exhibit mechanical properties such as fracture toughness that are intriguingly superior to their individual constituents. The scheme double-network preparation, however, is not equally successful for all polyelectrolyte/neutral pairs. A example poly(2-acrylamido-2-methyl-1-propane sulfonic acid) (PAMPS) network...

The dynamical behavior of hydration water sandwiched between 1,2-dimyristyl-sn-glycero-3-phosphocholine (DMPC) bilayers was investigated by quasi-elastic neutron scattering (QENS) in the range 275 and 316 K, where main transition temperature DMPC is interposed. results revealed that could be categorized into three types water: (1) free water, whose slightly different from bulk water; (2) loosely bound 1 order magnitude slower than (3) tightly comparable with molecules. number molecules per...

We report the surface sliding friction of a high strength gel against glass substrate under normal pressure range 0.01−2.5 MPa. The swollen with different viscous solvents is investigated over wide velocity range. A velocity−viscosity conversion relationship established. From relationship, master curve that characteristic to elastic−hydrodynamic transition observed. results indicate adsorption model proposed by our previous work valid even up MPa orders, which order cartilage sustains in...

A molecular mechanism is proposed for the toughness enhancement observed in double-network (DN) hydrogels prepared from poly(2-acrylamido-2-methyl-1-propanesulfonic acid) (PAMPS) polyelectrolyte network and poly(acrylamide) (PAAm) linear polymer. It an extension of phenomenological model set forth recently by Gong et al. ( Macromolecules 2007, 40, 6658- 6664 ). This rationalizes changes structure DN gel constituents via situ neutron scattering measurements, composition dependence solution...

Abstract Novel electro‐conductive and mechanically‐tough double network polymer hydrogels (E‐DN gels) were synthesized by polymerization of 3, 4‐ethylenedioxythiophene in the presence a hydrogel (DN gel) matrix. The E‐DN gels showed not only excellent mechanical performance, having fracture stress 1.4–2.1 MPa, but also electrical conductivity as high 10 −3 S cm −1 , both under dry water‐swollen states. energy gel was increased 1.7 3.4 times, respectively, compared with DN gel. From scanning...

In some synthetic polymers used for medical applications, hydration water in the vicinity of polymer chains is known to play an important role biocompatibility and referred as intermediate water. The crystallization below 0 °C observed during thermal analysis has been considered evidence presence However, origin physicochemical properties have not yet elucidated. this study, a typical biocompatible polymer, poly(ethylene oxide) its were investigated with use terahertz time-domain...

In this paper, the frictional behavior of a neutral hydrogel, polyvinyl alcohol (PVA), on smooth solid substrates with various levels hydrophobicity have been investigated in water using strain-controlled parallel-plate rheometer. For sliding velocity dependence friction, we detected distinct friction transition hydrophobic that are strongly adhesive to gel, while no clear was observed hydrophilic weakly gel. Even most substrate, maximum stress is approximately 1/10-1/5 gel's elastic modulus...

Interfacial structures of water at polyvinyl alcohol (PVA) and poly(2-acrylamido-2-methypropane) sulfonic acid sodium salt (PNaAMPS)/quartz interfaces were investigated by sum frequency generation (SFG) spectroscopy. Two broad peaks observed in OH stretching region 3200 3400 cm(-1), corresponding to the symmetric tetrahedrally coordinated, i.e., strongly hydrogen bonded "ice-like" water, asymmetric a more random arrangement, weakly "liquid-like" respectively, both cases. The became dominant...

We investigated the sliding friction between a soft hydrogel and rough weakly adhesive solid substrates in water environment. Polyvinyl alcohol (PVA) hydrogels of different elastic moduli two sets glass with contact angles to water, all which varied their surface roughness, were used. The measurement was performed by using strain-controlled parallel-plate rheometer. With an increase substrate low velocity region increased slightly, while it decreased significantly above critical on roughness...

A chemically cross-linked filamentous actin (F-actin) gel consisting of globular (G-actin) as repeating units was prepared. The F-actin by covalent bonds, and the main chain is represented self-assembly G-actin with a high-ordered hierarchical structure. exhibited good mechanical performance storage modulus >1 kPa undergoes reversible sol-gel transitions in response to changes salt concentration (chemical-induced transition) well shear strain (mechanical-induced transition). Therefore,...

A thermoresponsive 3D microtubule hydrogel (MT gel) was prepared by simultaneous polymerization and chemical cross-linking of tubulins. The main chain this gel is composed cross-linked MTs, which consists a cylindrical assembly tubulin covalently connected polyethylene glycol. This gel, contains 10 mg/mL tubulin, exhibits storage modulus G' as high 1 × 10(3), times higher than the loss G'' over wide range frequencies. MT reversible sol-gel transition temperature changes at 4-37 °C via...

The effects of water on the mechanical properties synthetic hydrophilic polymers with double-network (DN) structures were studied under different relative humidities (RH). It was found that they could sustain nearly same high Young's modulus as dry DN in RH range 10-80% (water content 3-17 wt %), is, more than 102 MPa. However, when exceeds 80%, abruptly absorb large amounts 90 %) and transform to a highly water-swollen "gel state" decrease 3 orders magnitude. Spectroscopic analyses revealed...

We studied the ability of surfactants to reduce friction by boundary lubrication for a bulk hydrogel sliding on solid surface in an aqueous solution. A piece negatively charged polyelectrolyte was slid across surfaces with various levels hydrophobicity, using strain-controlled parallel-plate rheometer water. dramatic reduction friction, especially low velocity region, detected addition surfactant water medium. This only observed gel–solid but not solid–solid indicating that soft and wet...

We study the sliding friction of poly(vinyl alcohol) (PVA) gel against glass substrate in hyaluronan (HA) aqueous solution with various concentrations and two molecular weights. The frictional stress decreases increase concentration HA at low velocity, lowest appears 10c* (c* is overlap concentration) solution; after that, it increases slightly concentration. By assuming that a continuous lubricant layer formed interface, which screens PVA adsorption to substrate, we estimate thickness...

We study the friction behaviors of poly(vinyl alcohol) (PVA) gel sliding against glass surface in dilute poly(ethylene oxide) (PEO) aqueous solution with various molecular weights, Mw, and concentrations. At low velocity (10-5, 10-4 m/s), distinct PEO polymer effects are observed: The frictional stress 2E4 (Mw = 2 × 104 g/mol) solutions is lower than that pure water, decreasing increase concentration reaching a minimum at crossover concentration, c*. However, higher weight solution, 4E6 4...

Hemoglobin, the vital O2 carrier in red blood cells, has long served as a classic example of an allosteric protein. Although high-resolution X-ray structural models are currently available for both deoxy tense (T) and fully liganded relaxed (R) states hemoglobin, much less is known about their dynamics, especially on picosecond to subnanosecond time scales. Here, we investigate dynamics CO forms human hemoglobin using quasielastic neutron scattering under near physiological conditions order...

Poly(ethylene oxide) (PEO) is a well-known biocompatible polymer and has widely been used for medical applications. Recently, we have investigated the dynamic behavior of hydration water in vicinity PEO chains at physiological temperature shown presence slow with diffusion coefficient one order magnitude less than that bulk water. This could be evidence intermediate critical biocompatibility; however, its detailed dynamical features were not established. In this article, analyze...

The side chain dynamics of poly(quinoxaline-2,3-diyl)s (PQXs) are expected to influence their conformation. To investigate these experimentally, quasielastic neutron scattering (QENS) was performed for PQXs in deuterated tetrahydrofuran (THF-d8) and 1,1,2-trichloroethane/THF (1,1,2-TCE-d3/THF-d8), which they formed right-handed left-handed helical structures, respectively. mean-square displacement the PQX chains 1,1,2-TCE-d3/THF-d8 lower than that THF-d8. Furthermore, QENS complementary...

Recently, it was reported that chitin and chitosan exhibited high-proton conductivity function as an electrolyte in fuel cells. In particular, is noteworthy proton the hydrated becomes 30 times higher than chitosan. Since necessary for cell electrolyte, significantly important to clarify key factor realization of conduction from a microscopic viewpoint future development Therefore, we have measured dynamics using quasi-elastic neutron scattering (QENS) compared mechanism between QENS results...