An evaluation of the characteristics of a stretchable ink wire suitable for the measurement of biological signals

We proposed a conductive ink wire for the measurement of biological signals, and evaluated its durability. The ink wire used was flexible and stretchable, strongly resisted water, and was painted on clothes. We considered the situation whereby the subject would wear the clothes, the clothes would deform and be exposed to perspiration. The ink wire could endure an elongation rate of at least 20% and a radius of curvature of a bend of at least 1.0?mm. The resistance of the wire increased with repeated deformation. However, the resistance could be reduced by annealing. Moreover, the ink wire did not deteriorate in a high-humidity environment (36?°C, 95% relative humidity). The insulation resistance of the wire under perspiration was sufficient to measure biological signals. Furthermore, we produced an undershirt composed of electrodes and wires made of the proposed ink, and demonstrated the ability of ink wires to measure the electrocardiogram (ECG) signals. Experiments showed that the ECG signals passing through the undershirt were not affected by deformation of the wire.     

Development of a Quantitative Visualization Technique for Gluten in Dough Using Fluorescence Fingerprint Imaging

The distribution of constituents in food affects its end qualities such as texture, and there is a growing demand to develop a method for studying this distribution easily, accurately, and nondestructively. The objective of this study was to develop an imaging method that visualizes the precise quantity of constituents, using the fluorescence fingerprint (FF). The FF is a set of fluorescence spectra acquired at consecutive excitation wavelengths, and its pattern contains abundant information on the constituents of the sample measured. In this study, the target for visualization was the distribution of gluten in dough samples. Dough samples were prepared with different ratios of gluten, starch, and water, and fluorescence images at multiple combinations of excitation and emission wavelengths were acquired. The fluorescence intensities of a pixel at these different wavelengths constructed its FF, reflecting the constituents of the corresponding point in the sample. A partial least squares regression (PLSR) model was built using the average FFs of the samples and the corresponding gluten ratios as the explanatory and objective variables, respectively. The importance of each wavelength in the PLSR model was assessed using the selectivity ratio, and optimum wavelengths for the accurate prediction of gluten ratio were selected. Finally, the gluten ratio of each pixel was predicted with the PLSR model using the selected wavelengths, and each pixel was colored according to the predicted gluten ratio. The imaging method developed enables the distribution of constituents to be visualized with colors corresponding to their actual quantities or ratios.     

Preparation of bifunctional chelating fiber containing iminodi(methylphosphonate) and sulfonate and its performances in column-mode uptake of Cu(II) and Zn(II)

The bifunctional chelating fiber, FNPS, was prepared from vinylbenzyl chloride (CMS) grafted polyethylene-coated polypropylene fiber (PPPEf-g-CMS). In addition to the primary iminodi(methylphosphonate) chelating groups, FNPS has sulfonate groups as secondary functional group. FNPS was prepared by the following four steps. First, PPPEf-g-CMS was reacted with potassium phthalimide to substitute chlorine atoms in PPPEf-g-CMS with phthalimide groups. Second, sulfonate groups were introduced into the phenyl groups of benzyl moieties on the grafted polymer chains by the reaction with 95% sulfuric acid. Third, phthalimide moieties were hydrolyzed with ethanol solution of hydrazine hydrate to give the primary amino groups at the end of benzyl moieties on the grafted chains. Finally, these primary amino groups were converted into iminodi(methylphosphonate) groups by Mannich condensation reaction, in which the precursory fiber was reacted with large excess phosphorous acid and paraformaldehyde in 6 M hydrochloric acid media under the refluxed conditions for 6 h. The sulfonate and iminodi(methylphosphonate) groups in the resulting FNPS were identified by FT-IR spectroscopy. Contents of nitrogen, phosphorus, and sulfur in FNPS were found to be 1.53, 2.80, and 0.99 mmol/g, respectively. The phosphorus to nitrogen molar ratio was 1.83. This is very close to the ideal value of 2. The sulfur to nitrogen molar ratio was 0.65. The column-mode test on the Cu(II) uptake from a 0.1 mM Cu(II) aqueous solution revealed that FNPS can take up Cu(II) rapidly even in the extremely high feed flow rate range from 1000 to 7000 h^?1 in space velocity. The breakthrough capacity of FNPS for Cu(II) is as high as ca. 0.8 mmol/g at the flow rate of 7000 h^?1. In addition, it is expected that the FNPS packed column will make it possible to purify huge volumes of waters contaminated with 10^?4 M levels of Zn(II), as long as the concentrations of the co-existing Ca(II) and Mg(II) are nearly equal to those in river waters.     

Poly[(3-hexylthiophene)-block-(3-semifluoroalkylthiophene)] for Polymer Solar Cells

We report the synthesis of poly[(3-hexylthiophene)-block-(3-(4,4,5,5,6,6,7,7,7-nonafluoroheptyl)thiophene)], P(3HT-b-3SFT), carried out by the Grignard Metathesis Method (GRIM). The copolymers composition was determined by (1)H and (19)F NMR spectroscopies, and gel permeation chromatography (GPC). The thin films of P(3HT-b-3SFT) were investigated by ultraviolet-visible absorption spectroscopy and atomic force microscopy (AFM). We also fabricated bulk-hetero junction (BHJ) solar cells based on blends of P(3HT-b-3SFT) and [6,6]-phenyl-C(61)-butyric acid methyl ester (PCBM). Although the composition ratio of P3SFT in P(3HT-b-3SFT) was low, the influence of P3SFT on the morphology and properties of solar cells was significant. The annealing process for the BHJ solar cells induced the formation of large domains and led to poor solar cell performance. The BHJ solar cells, based on PCBM and P(3HT-b-3SFT), prepared by the non-annealing process, had a maximum power conversion efficiency of 0.84% under 100 mW/cm(2) (AM 1.5 solar illumination) in air.     

Influence of chemical compositions on the properties of random and multiblock sulfonated poly(arylene ether sulfone)‐based proton‐exchange membranes

The influence of chemical compositions on the properties of sulfonated poly(arylene ether sulfone)‐based proton‐exchange membranes was studied. First, we synthesized three different series of random SPAES copolymers using three kinds of hydrophobic monomers, including 4,4′‐dihydroxyldiphenylether, 2,6‐dihydroxynaphthalene (DHN), and 4,4′‐hexafluoroisopropylidenediphenol (6F‐BPA) to investigate effects of hydrophobic components on the properties of SPAES membranes as proton‐exchange membranes. Random SPAES copolymers with 6F‐BPA showed the highest proton conductivity while random SPAES copolymers with DHN displayed the lowest methanol permeability among the three random copolymers. Subsequently, we synthesized multiblock SPAES using the DHN as a hydrophobic monomer and studied the effect of the length of hydrophilic segments in the multiblock SPAES copolymers on membrane performance. The results indicated that longer hydrophilic segments in the copolymers led to higher water uptake, proton conductivity, and proton/methanol selectivity of membranes even at low humidity. In addition, the morphology studies (AFM and SAXS measurements) of membranes suggested that multiblock copolymers with long hydrophilic segments resulted in developed phase separation in membranes, and ionic clusters formed more easily, thus improving the membrane performance. Therefore, both the kinds of hydrophobic monomers and the length of hydrophilic segments in SPAES copolymers would influence the membranes performance as proton‐exchange membranes. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Thermal and mechanical properties of photocured organic–inorganic hybrid nanocomposites of terpene‐based acrylate resin and methacrylate‐substituted polysilsesquioxane

Diacrylate compounds derived from α‐pinene and limonene (TDAs: TDA‐1 and TDA‐2) were photocured with methacryl‐substituted polysilsesquioxane (ME‐PSQ) prepared from 3‐(trimethoxysilyl)propyl methacrylate and tetramethylammonium hydroxide (TMAOH) in the TDA/ME‐PSQ weight ratio of 20 : 0, 20 : 1, 20 : 2, 20 : 3, and 20 : 4. All the photocured TDA/ME‐PSQ hybrid nanocomposites became transparent. The thermomechanical analysis of the cured TDA/ME‐PSQ revealed that the glass transition temperature (T_g) increased, the thermal expansion coefficient above T_g decreased with increasing ME‐PSQ content, and that the TDA‐1/ME‐PSQ had ca. 30°C greater T_g than the TDA‐2/ME‐PSQ with the same ME‐PSQ content. Also, the dynamic mechanical analysis revealed that the TDA‐1/ME‐PSQ had much greater storage modulus at around 150°C than the corresponding TDA‐2/ME‐PSQ. The flexural strength and modulus of the TDA/ME‐PSQ nanocomposites at 20°C had maximum at ME‐PSQ content 4.8 and 13.0 wt %, respectively. As a whole, the thermal and mechanical properties of the nanocomposites were improved by the addition of ME‐PSQ, and those of TDA‐1/ME‐PSQ nanocomposites were superior to those of TDA‐2/ME‐PSQ. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Whisker mitigation measures for Sn-plated Cu for different stress tests

The effectiveness of the widely-used whisker mitigation measures for Sn-plated Cu base material (annealing at 150 °C for 1 h or a Ni interlayer) were investigated after temperature cycling and after storage at room temperature. It was found that these measures prevent whisker growth during isothermal storage, but not during temperature cycling. These mitigation measures do apparently not reduce the compressive stress that builds up during temperature cycling due to different coefficients of thermal expansion of Sn and Cu. A change of the Sn microstructure to globular grains is proposed and investigated as potential whisker mitigation measure for temperature cycling.     

Direct polymer-transfer lithography for high-throughput fabrication of Cu line patterns

A novel direct polymer-transfer lithography (DPTL) technique is proposed for fabricating fine patterns having feature sizes ranging from ten to several tens of micrometers with extremely high throughput. By means of this technique, a homemade fluorine-containing polymer “ink”, which has good water repellency, was imprinted directly onto a Cu/polyimide sheet by using an elastomeric polydimethylsiloxane (PDMS) stamp; imprinting was followed by wet etching of the Cu layer, with the transferred polymer patterns serving as an etch mask. Under the optimized imprinting conditions, Cu lead patterns with a minimum line width of approximately 10 μm were successfully fabricated with high accuracy and good reproducibility. The DPTL technique will be very useful for manufacturing flexible printed circuit boards (FPCs).     

Bright nickel film deposited by supercritical carbon dioxide emulsion using additive-free Watts bath

This paper is aimed on studying film smoothening effect of supercritical carbon dioxide emulsion (Sc-CO₂-E) on nickel film electroplated using an additive-free Watts bath. Morphology of nickel film electroplated with Sc-CO₂-E was found to be similar to that of nickel film prepared from electroless plating. Surface roughness (R_a) of nickel film electroplated with Sc-CO₂-E was lower than that of nickel film electroplated through conventional method. A minimum R_a was found for nickel film electroplated through conventional method and Sc-CO₂-E when increasing current density from 0.010 to 0.150 A/cm². The minimum R_a was 69.8 nm at 0.020 A/cm² and 14.0 nm at 0.030 A/cm², respectively for conventional and Sc-CO₂-E case. After the minimum point, increasing rate of R_a increased was lower for Sc-CO₂-E case; this was because of higher hydrogen solubility in Sc-CO₂. Grain size of nickel film electroplated with Sc-CO₂-E was found to be finer than that of conventional case.     

A mass balance approach for evaluating leachable arsenic and chromium from an in-service CCA-treated wood structure

Many existing residential wood structures, such as playsets and decks, have been treated with chromated copper arsenate (CCA). This preservative chemical can be released from these structures incrementally over time through contact with rainfall. The objective of this study was to evaluate the levels of arsenic and chromium leached from an in-service CCA-treated deck exposed to rainfall, as well as their possible impacts on soils and shallow groundwater. Two monitoring stations, one containing a CCA-treated deck and the other containing an untreated deck as a control, were constructed outside for this study. Rainfall, runoff water from the decks, soils below the decks, and infiltrated water through 0.7-m depth of soil were monitored for arsenic and chromium over a period of 3 years. The concentration of the CCA-treated deck runoff for arsenic (0.114-4.66 mg/L) and chromium (0.008-0.470 mg/L) were significantly (p<0.001) higher than the untreated deck runoff (< or =0.002 mg/L for both). During the 3-year monitoring period, 13% of the arsenic and 1.4% of the chromium were leached from the amount initially present in the CCA-treated wood. Arsenic levels (<0.1-46 mg/kg) in soils under the CCA-treated deck were significantly (p<0.001) higher than under the untreated deck (<0.1-2.7 mg/kg), while chromium levels were statistically the same below the two decks (2.4-9.6 mg/kg). Approximately 94% of the arsenic from the runoff was absorbed in the soils below the CCA-treated deck; the upper 2.5 cm of the soils captured 42% of the total. The infiltrated water concentrations for arsenic (<0.001-0.085 mg/L) and chromium (<0.001-0.010 mg/L) below the CCA-treated deck were both significantly (p<0.001) higher than below the untreated deck (< or =0.006 mg/L). The amounts of arsenic found in the infiltrated water below the CCA-treated deck represented 6% of total arsenic leached and less than 0.7% of the initial mass in the wood. The study demonstrated that exposure of a CCA-treated deck to rainfall resulted in elevated arsenic concentrations in both runoff and soil. Although only a relatively small fraction of the initial arsenic from the wood was found to infiltrate through the soil, these impacts were significant and caused the infiltrated water to exceed drinking water standards. The study suggests that potential exposures to arsenic exist indirectly through an environment that is contaminated with arsenic leached from in-service CCA-treated wood.