Diffusional behavior of multi-arm star polymers by H pulsed field gradient spin-echo NMR method

The diffusional behavior of multi-arm star-shaped p(tBMA) was investigated in a concentration range from dilute to semidilute region with ¹H pulsed field gradient spin-echo NMR (PFGSE-NMR). An 142-arm star-shaped p(tBMA) showed two diffusional mode, which reflected the coexistence of liquid ordering phase and liquid phase near the ordering transition. On the other hand, for star-shaped p(tBMA) with 55 arms showed a single diffusional relaxation in all concentration ranges during observation time. In the semidilute region, the relationship between the diffusion coefficient against the polymer concentration was affected strongly not only the arm number but also liquid ordering structure.     

Effect of the addition of silver compounds during the pyrolysis of manganese nitrate on tantalum anodic oxide film

A study of the pyrolysis of an aqueous solution of manganese nitrate in the presence of silver compounds has been carried out. Thermal analysis showed that the MnO₂ formation temperature and the transformation temperature from MnO₂ to Mn₂O₃ shifted towards a lower temperature in the presence of silver acetate. A large particle-size and high crystallinity MnO₂ was formed; this may be a useful method of making an excellent tantalum capacitor with high capacitance.     

Inter- and intra-molecular ionic interactions of polyampholyte: Carboxymethyl-2-diethylaminoethylcellulose

Carboxymethyl-2-diethylaminoethylcellulose (CM-DEAE cellulose) was prepared by etherification of carboxymethylcellulose with diethylaminoethyl chloride in a NaOH solution. The behaviour of CM-DEAE cellulose in aqueous solution was studied by viscosity and GPC measurements. The degree of substitution (DS) and existing states of DEAE substituents were examined by the use of proton NMR, and those of the CM substituents were observed with FT-IR. The results reveal that the reduced viscosity and apparent molecular size of CM-DEAE cellulose vary with the concentration of sodium chloride and changes in pH and DS. These phenomena can be explained in terms of inter- and intra-molecular ionic interactions.     

Synthesis of polyethylene oxide end‐capped with perfluoroalkyl groups/polystyrene prototype brushes

Polystyrene (PS)/poly(ethylene oxide) (PEO) prototype brushes were prepared by alternating free‐radical copolymerization of methacryloyl‐terminated PS and α‐vinylbenzyl‐ω‐hydroxy or α‐vinylbenzyl‐ω‐perfluoroalkyl (R_f) PEO macromonomers with the addition of Lewis acid (SnCl₄). It was found from their dilute‐solution properties that PS/PEO end‐capped with R_f (PBR_f), and PS/PEO having OH groups at terminal ends (PBOH) prototype brushes formed a single molecule in benzene and aggregates in chloroform, respectively. However, the brush PBOH formed a single molecule in N,N‐dimethylformamide. Such aggregation behaviors seemed to be caused by the interaction between hydroxy groups of PEO chain ends. The brush PBOH was also converted into PBR_f‐type brush by chemical modification, using corresponding acid chloride. The substitution of R_f groups was ～70% due to slipping of terminal hydroxy groups into PEO internal domains. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 772–778, 2006     

Immobilization of multicopper oxidase from Pyrobaculum aerophilum onto an electrospun-aligned single-walled carbon nanotube surface via a carbon-nanotube-binding peptide for biocathode

Biofuel cells (BFCs) that produce electrical energy from organic resources through enzymatic reactions have been attracting significant attention. Owing to the high electrical conductivity of carbon nanotubes (CNTs), their modification on the electrode surface of a BFC is expected to increase the current, and their high specific surface area may be useful in increasing the power output. Previously, we constructed a biocathode by immobilizing multicopper oxidase from Pyrobaculum aerophilum (McoP) with a carbon nanotube binding peptide (CBP) sequence on the CNTs. This resulted in higher current densities than when using enzymes without CBP sequences. However, owing to the randomly stacked CNTs on the surface of the electrodes, their conductive properties were impaired and performance as biocathodes was poor. Herein, we constructed a biocathode in which single-walled CNTs (SWCNTs) were oriented one-dimensionally and McoP is immobilized on the surface of an SWNCT via CBP. The current density was successfully increased by two-fold by orienting the CNTs and orienting and immobilizing McoP on their surfaces. This technology provides insights into the development of biodevices with controlled orientation of both the SWCNTs and enzymes immobilized on their surfaces.     

Boronic acid‐based thin films that show saccharide‐responsive multicolor changes

A novel saccharide sensor that displays a distinct color change resembling a “traffic signal” was developed. By copolymerizing boronic acid and amine monomers on a glass plate, a boronic acid‐containing thin film was obtained. Anionic blue and yellow dyes were adsorbed on the thin film, and the film was immersed in aqueous saccharide solutions containing a cationic red dye. With increase in the saccharide concentration in the solution, the thin film changes color from green to red via yellow. The observed distinct changes in color were attributed to a stepwise release and binding of dyes. The sensitivity of the saccharide sensor was dependent on the monomer composition of the thin film and increased with increasing the boronic acid content. The pH of the saccharide solution was another key factor affecting the sensing behavior, and glucose‐responsive color changes were significantly enhanced at pH 7.8. By optimizing these conditions, significant color changes in response to glucose were achieved. Saccharide selectivity was found to be in the following order: fructose > glucose > galactose = mannose > sucrose. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42679.     

Scaling prospect of optically differential reconfigurable gate array VLSIs

Dynamic reconfigurable devices present new computational paradigms because programmable devices’ activity and performance can be improved dramatically by increasing its reconfiguration frequency. Therefore, this paper presents designs of optically differential reconfigurable gate array (ODRGA) VLSIs using 0.18 μm and 0.35 μm CMOS process technologies. Although they are a type of programmable gate array, they can be reconfigured optically in nanoseconds. This paper also discusses future scaling prospects of ODRGA-VLSIs.     

Surface Waves on Superfluid <Superscript>4</Superscript>He Under Reduced Gravity

Superfluid ⁴He was produced on a small jet plane for the first time using a small GM-refrigerator to condense the liquid and a scroll pump to get the superfluid by evaporation. The surface wave on superfluid under 0.5g _E, 0.1g _E and 0.05g _E, together with 2g _E and 1g _E, was successfully examined by an optical method utilizing parabolic flight. Here, g _E is the gravitational constant on the ground. Assuming that only the fundamental mode was excited as determined by the sample cell width, the resonance peak in the frequency domain was well reproduced by the gravity wave with corresponding gravity constant.     

Novel synthesis of branched polystyrenes by quasi‐living radical copolymerization using photofunctional inimer

Branched polystyrenes were prepared by quasi‐living radical copolymerization of N,N‐diethylaminodithiocarbamoylmethylstyrene (inimer: DTCS) with styrene under UV irradiation. DTCS monomers play an important role in this copolymerization system as an inimer capable of initiating living radical polymerization of the vinyl group. Two monomers (DTCS and styrene) showed equal reactivity toward both propagating species, and the copolymer composition was the same as the comonomer feed. This result means that both the branching and chain length of the hyperbranched molecules can be controlled statistically by the feed monomer ratios. The compact nature of the branched macromolecules is demonstrated by viscosity measurements compared to the linear analogues. © 2001 Society of Chemical Industry     

Fast and Almost Complete Nitridation of Mesoporous Silica MCM-41 with Ammonia in a Plug-Flow Reactor

The title reaction proceeded well to yield silicon (oxy)nitride at 973–1323 K using a plug-flow reactor. The degree of nitridation was studied as a function of temperature and time of nitridation, the sample weight, and the flow rate of ammonia. It was dependent on the reaction temperature and the amount of ammonia supplied per sample weight. The nitridation at 1273 K for 10–25 h yielded the oxynitride with 36–39 wt% nitrogen, which was very close to 40 wt% of Si₃N₄. Characterization with X-ray diffraction, field-emission scanning electron microscopy and transmission electron microscopy measurements, and nitrogen adsorption revealed the conversion of MCM-41 to the corresponding oxynitride without essential loss of the mesoporous structure, the decrements of the lattice constant and the pore diameter by 20–35%, and the increments of the wall thickness by ca. 45%. Solid-state ²⁹Si nuclear magnetic resonance spectra during the nitridation clearly showed fast decrease in SiO₄ species and slow in SiO₃(OH). Various intermediate species, SiO _x N _y (NH₂ or NH) _z , were observed to be formed and finally, ca. 70% SiN₄ species, ca. 20% SiN₃(NH₂ or NH), and ca. 10% SiON₂(NH₂ or NH) were produced, being consistent with the results of the above mentioned elemental analysis.