Incremental vapor sorption in a phase-segregated polyurethane elastomer

Incremental vapor sorption and desorption runs have been carried out with o-dichlorobenzene (ODCB) a strongly swelling solvent, in 2, 6, and 10 mil polyether polyurethane films. Two-stage sorption behavior occurs at intermediate and higher concentrations but is generally absent in the desorption runs. Analysis of the two-stage curves, using the Berens-Hopfenberg model of independent Fickian diffusion and first-order relaxation processes, leads to apparent diffusion coefficients which increase with thickness and show a pronounced maximum with concentration, whereas the relaxation rate constant decreases with concentration. Correction for the pressure drift during the runs, due to the low vapor pressure of ODCB, reduces the thickness dependence. The negative concentration dependence of the relaxation rate constant is related to the distribution of microdomain stabilities. Calculated values of the self-diffusion coefficient show that the maximum in the apparent diffusion constant with concentration can be accounted for largely, but not entirely, by the thermodynamic contributions. It is proposed that the additional factor is relaxation-controlled swelling which arises from the strong coupling between the matrix and hard-segment responses.     

Effect of alkali metal salts on decomposition of ionic liquid like organic salt

N ¹,N ¹,N ²,N ²-tetramethylethane-1,2-diamine-based ionic salts (TMEDA), N ¹,N ¹,N ¹,N ²,N ²,N ²-hexamethylethane-1,2-diaminium dicyanamide (HMEDA-(DCA)₂) were prepared following the quaternization and subsequent ion exchange. The chemical structure of the HMEDA-(DCA)₂ was confirmed using ¹³C NMR spectrum and elemental analysis. The corresponding viscosity of its 60 wt% solution was found to be lower than 5 cP at room temperature, which was critical for propellant application. The ignition delay of 40 wt% HMEDA-(DCA)₂ solution was decreased to 20–30 ms dramatically using alkali metal salts, Li(CH₃COO), Mg(CH₃COO)₂, and Ca(CH₃COO)₂ as a co-catalyst when white fume nitric acid was utilized as an oxidizer.     

Evaluation of Metabolite Profiles of Ginseng Berry Pomace Obtained after Different Pressure Treatments and Their Correlation with the Antioxidant Activity

Ginseng berry pomace (GBP) is a byproduct of ginseng berry processing and is rich in numerous bioactive components, including ginsenosides and their derivatives. The application of GBP as a beneficial biomaterial is currently limited. In this study, we aimed to evaluate their potential as a promising source of bioactive compounds using metabolite profiling. The GBP obtained after different ultra-high-pressure (UHP) treatments was analyzed by GC-TOF-MS and UHPLC-LTQ-Orbitrap-MS/MS. In multivariate analyses, we observed a clear demarcation between the control and UHP-treated groups. The results demonstrated that the relative abundance of primary metabolites and a few ginsenosides was higher in the control, whereas UHP treatment contained higher levels of fatty acids and sugars. Furthermore, GBPs were fractionated using different solvents, followed by UHPLC-LTQ-Orbitrap-MS/MS analyses. The heatmap revealed that phenolics (e.g., quercetin, kaempferol) and fewer polar ginsenosides (e.g., F4, Rh2) were abundant in the ethyl acetate fraction, whereas the levels of lignans (e.g., 7-hydroxysecoisolariciresinol, syringaresinol) and fatty acids (e.g., trihydroxy-octadecenoic acid, oxo-dihydroxy-octadecenoic acid) were high in chloroform. Correlation analysis showed that phenolics, less polar ginsenosides, and fatty acids were positively correlated with the antioxidant activity of GBP. Our study highlights GBP as a functional ingredient for the development of high-quality ginseng berry products.     

Development of Au−Pd catalysts supported on carbon for a direct borohydride fuel cell

The purpose of this study is to diminish the hydrolysis of borohydride with good performances of a direct borohydride fuel cell (DBFC). Pd/C is considered as a proper anode catalyst for the DBFC. Au/C has lower activity for a hydrolysis reaction than other catalysts such as nickel, palladium, platinum, etc. Au?Pd catalysts supported on carbon (Au?Pd/C) were prepared with different weight ratios, 1∶3, 2∶2 and 3∶1. The performances of three different catalysts increased with the amount of Pd, while the hydrogen evolution rates were similar. Consequently, the catalysts prepared with a Au/Pd weight ratio of 1∶3 showed the best performance.     

Magnetic assistance highly sensitive protein assay based on surface-enhanced resonance Raman scattering

A simple and effective surface-enhanced Raman scattering (SERS)-based protocol for the detection of protein-small molecule interactions has been developed. We employed silver-coated magnetic particles (AgMNPs), which can provide high SERS activity as a protein carrier to capture a small molecule. Combining magnetic separation and the SERS method for protein detection, highly reproducible SERS spectra of a protein-small molecule complex can be obtained with high sensitivity. This time-saving method employs an external magnetic field to induce the AgMNPs to aggregate to increase the amount of atto610-biotin/avidin complex in a unit area with the SERS enhancement. Because of the contribution of the AgMNP aggregation to the SERS, this protocol has great potential for practical high-throughput detection of the protein-small molecule complex and the antigen-antibody immunocomplex.     

Nanoparticle-induced morphology and hydrophilicity of structured surfaces

Nanoparticles have been applied into the construction of micro- and nanoscaled surface structures with extreme wettability over the past few years. However, the details of processing and employing colloidal nanosuspensions for this purpose have not yet been fully investigated. In this work, we study the surface structures formed via nanosuspensions, in which nanoparticles of solid phase are presented, and the caused surface wettability. We disperse silica nanoparticles with different sizes into pure ethanol to prepare nanosuspensions with a series of concentrations. The suspensions are ultrasonically processed to prompt uniform distribution of nanoparticles before application. The deposited nanosuspensions are thermally treated to assist the regulation of surface patterns based on nanoparticles. Hence, the investigation explores a variety of experimental conditions that will lead to distinctive surface structures and wettabilities. Accordingly, the wettability of the induced surfaces is investigated using contact angle measurement, and the structures of those surfaces are mainly revealed by atomic force microscopy (AFM). Superhydrophilicity is observed on many of such formed surfaces, and the pattern of surface structures in micro- and nanoscale is closely related to the processing conditions and the size of nanoparticles. Thus, we report the characteristics of the surface patterns based on nanoparticles and the formed wettability.     

Synthesis of metal-hydrazone complexes and vapochromic behavior of their hydrogen-bonded proton-transfer assemblies

We synthesized and investigated a new series of metal-hydrazone complexes, including deprotonated [MX(mtbhp)] and protonated forms [MX(Hmtbhp)](ClO(4)) (M = Pd(2+), Pt(2+); X = Cl(-), Br(-); Hmtbhp = 2-(2-(2-(methylthio)benzylidene)hydrazinyl)pyridine) and hydrogen-bonded proton-transfer (HBPT) assemblies containing [PdBr(mtbhp)] and bromanilic acid (H(2)BA). The mtbhp hydrazone ligand acts as a tridentate SNN ligand and provides a high proton affinity. UV-vis spectroscopy revealed that these metal-hydrazone complexes follow a reversible protonation-deprotonation reaction ([MX(mtbhp)] + H(+) ? [MX(Hmtbhp)](+)), resulting in a remarkable color change from red to yellow. Reactions between proton acceptor [PdBr(mtbhp)] (A) and proton donor H(2)BA (D) afforded four types of HBPT assemblies with different D/A ratios: for D/A = 1:1, {[PdBr(Hmtbhp)](HBA)·Acetone} and {[PdBr(Hmtbhp)](HBA)·2(1,4-dioxane)}; for D/A = 1:2, [PdBr(Hmtbhp)](2)(BA); and for D/A = 3:2, {[PdBr(Hmtbhp)](2)(HBA)(2)(H(2)BA)·2Acetonitrile}. The proton donor gave at least one proton to the acceptor to form the hydrogen bonded A···D pair of [PdBr(Hmtbhp)](+)···HBA(-). The strength of the hydrogen bond in the pair depends on the kind of molecule bound to the free monoanionic bromanilate OH group. Low-temperature IR spectra (T < 150 K) showed that the hydrogen bond distance between [PdBr(Hmtbhp)](+) and bromanilate was short enough (ca. 2.58 ?) to induce proton migration in the [PdBr(Hmtbhp)](2)(BA) assembly in the solid state. The hydrogen bonds formed not only between [PdBr(Hmtbhp)](+) and HBA(-) but also between HBA(-) and neutral H(2)BA molecules in the {[PdBr(Hmtbhp)](2)(HBA)(2)(H(2)BA)·2Acetonitrile} assembly. The H(2)BA-based flexible hydrogen bond network and strong acidic host structure result in an interesting vapor adsorption ability and vapochromic behavior in this assembly because the vapor-induced rearrangement of the hydrogen bond network, accompanied by changes in π-π stacking interactions, provides a recognition ability of proton donating and accepting properties of the vapor molecule.