Effects of pH and concentration on ability of Cl<Superscript>−</Superscript> and NO<Stack><Subscript>3</Subscript><Superscript>−</Superscript></Stack> to intercalate into a hydrotalcite-like compound during its synthesis

In this study, we confirmed that the characteristics of anion intercalation into the interlayer of a hydrotalcite-like compound (HT) during synthesis are similar to those of the anion-exchange reaction of HTs as well as the reconstruction reaction of HTs from Mg-Al oxide. We demonstrated that (i) Cl⁻, which has a higher charge density than NO₃⁻, more easily reacted with Mg and Al species to form HT structure, resulting in greater intercalation of Cl⁻ into the HT interlayer; and (ii) for HTs with lower Mg: Al molar ratios, OH⁻, which has a higher charge density than Cl⁻ and NO₃⁻, was more likely to interact with Mg and Al species to form HT structure, blocking the intercalation of Cl⁻ and NO₃⁻. Furthermore, we showed that high concentrations of Cl⁻ and NO₃⁻ in solution regulated their intercalation into the HT interlayer. The high activity of Cl⁻ and NO₃⁻ in solution would facilitate the anions’ reactions with Mg and Al species to form HTs, resulting in a high degree of anion intercalation into the interlayer of HTs.     

Arsenic speciation in rice and soil containing related compounds of chemical warfare agents

Diphenylarsinic acid, phenylarsonic acid, methylphenylarsinic acid (MPAA), dimethylphenylarsine oxide (DMPAO), and methyldiphenylarsine oxide (MDPAO) in soil and rice were extracted, separated by reversed-phase chromatography, and quantified by ICPMS with a membrane desolvating system. For the extraction of arsenicals from rice grain and straw, 68% HNO3 provided better extraction efficiency than water, 50% methanol, or 2.0 mol L(-1) trifluoroacetic acid. For the extraction from soil, 68% HNO3 provided better extraction efficiency than H2O, 1 mol L(-1) H3PO4, or 1 mol L(-1) NaOH. The contaminated soil contained all five aromatic arsenicals along with inorganic arsenicals as main species (5.86 +/- 0.19 microg of As kg(-1): 60.8 +/- 2.0% of total extracted As). After pot experiments, rice straw contained mainly DMPAO (7.71 +/- 0.48 microg of As kg(-1): 60.5 +/- 3.7%), MDPAO (0.91 +/- 0.07 microg of As kg(-1): 7.2 +/- 0.5%), and inorganic As (2.85 +/- 0.20 microg of As kg(-1): 22.3 +/- 1.6%). On the other hand, rice grain contained mainly MPAA (1.17 +/- 0.04 microg of As kg(-1): 86.7 +/- 2.7%). The root uptake of each species from the soil and transport from straw to grains were significantly related to the calculated log K(ow) values.     

Stable organic thin-film transistors using full solution-processing and low-temperature sintering silver nanoparticle inks

We have fabricated electronically stable organic thin-film transistor (TFT) devices that are fully solution-processed and adopt printed electrodes using silver nanoparticles dispersed in organic solvents, whose sintering temperatures are 100 °C or less. The bottom-contact organic TFT devices showed good electrical characteristics, and exhibited threshold voltage shifts less than 2.0 V after applying a DC bias voltage stress for 10⁴ s, which is attributed to relatively low contact resistance. These results demonstrate the feasibility of producing stable organic TFTs that are fully solution-processed at relatively low temperatures, for use in large-area flexible electronics applications.     

A novel water-repellent o/w emulsion using a new water-soluble amphiphilic polymer

A novel O/W (oil-in-water) emulsion cosmetic that has strong water repellency and a >>water-splash feel« was prepared using the amphiphilic polymer hydrophilic-hydrophobic modified polysaccharide (INCI/Sodium Stearoxy PG-Hydroxyethylcellulose Sulfonate). This emulsion is composed of a hydrophobic–hydrophilic modified polysaccharide/water/oil system with a small amount of lipophilic non-ionic surfactant (hydrophilic–lipophilic balance<5) added to obtain finely emulsified oil particles. Hydrophilic–hydrophobic modified polysaccharide was used as a thickener and polymer surfactant, and it produced a stable O/W emulsion without the addition of a hydrophilic surfactant. Several types of oil droplets decrease in size upon addition of various kinds of lipophilic surfactant due to the lowering of tension at the water/oil interface. Rheological measurements revealed that the strong network structure of hydrophilic–hydrophobic modified polysaccharide retained oil droplets without occurrence of phase inversion. Such an emulsion is very different from those made using conventional hydrophilic surfactants, and it is water repellent. This system was characterized by the presence of hydrophilic–hydrophobic modified polysaccharide, and the state of the emulsion could be controlled by the ratio of hydrophobic/hydrophilic moieties introduced into the polysaccharide.