Arrays of linear, one-dimensional (1D) silver nanoparticle rows have been synthesized that demonstrate strong surface enhanced Raman scattering (SERS) that is dependent on the polarization of the incident electromagnetic radiation. Ordered arrays of 1D rows of spherical silver nanoparticles were fabricated on highly oriented pyrolytic graphite (HOPG) by physical vapor deposition (PVD) at 400 °C. Scanning electron microscopy confirmed the formation of arrays of highly parallel rows of nanoparticles. The rows are typically hundreds of microns long with particle gaps less than 10 nm and 10−1000 nm spacing between adjacent 1D rows. The polarization dependence of the SERS was characterized using thiophenol as a Raman probe molecule that was adsorbed as a monolayer on the silver nanoparticle surfaces. When incident light is polarized along the axis of the nanoparticle rows, the intensity of the Raman-scattered light was ≈20 times stronger than Raman scattered light when the incident radiation was polarized perpendicular to the axis of the nanoparticle rows. This polarization selectivity is in good agreement with our calculations that explore the electromagnetic response of the interacting nanoparticles with an incident light field.

No abstract

Nylon–cotton (NC) blend fabrics are widely used in military and industrial applications, but their high flammability still remains a serious problem. In an effort to effectively and quickly impart flame retardancy to the NC fabric, it was treated by simply blade coating with a Cu2+-doped polyelectrolyte complex (CPEC) that consists of ammonium polyphosphate (APP), polyethylenimine (PEI), and copper sulfate. The viscosity of the CPEC can be adjusted by altering the content of CuSO4, which controls the amount of extrinsic and intrinsic ion pairs. By adjusting the proportion and content of PEI, APP, and CuSO4, CPEC suitable for treating the NC fabric was obtained. Only 0.067 wt % Cu2+ was needed to adjust the viscosity and impart self-extinguishing behavior in a vertical burning test. This simple two-step treatment provides a promising technology to protect flammable polymeric substrates with ultralow metal-doped polyelectrolyte complexes.

No abstract

Photo finish: Zinc‐substituted cytochrome b562 (Zn‐cyt b562) immobilized on a gold electrode is an n‐type photodiode, whereas zinc‐cytochrome c (Zn‐cyt c) is a p‐type photoconductor (see picture). DFT calculations indicate that the cytochrome band gaps are much lower than those estimated for smaller polypeptides. The semiconductor properties of these proteins depend on the charge distribution on their molecular surfaces.

By multicomponent mechanical blending technology, water‐swelling rubber (WSR) was prepared through choosing chlorinated polyethylene (CPE), a superabsorbent polymer (cross‐linking poly(sodium acrylate), CPNaAA), and compatibilizer (poly(methyl methacrylate‐co‐maleic anhydride), P (MMA‐co‐MAH)) along with other minor additives. P (MMA‐co‐MAH) was synthesized by grafting maleic anhydride (MAH) onto methyl methacrylate (MMA). Microstructure, water‐absorbent properties, and mechanical properties of WSR were investigated. The results showed that P (MMA‐co‐MAH) boosted the dispersibility between CPNaAA and CPE and led to the increase in Shore A hardness, tensile strength, tensile stress at 100%, and water‐swelling behavior, whereas the elongation at break and weight loss were decreased with P (MMA‐co‐MAH) content. When the content of P (MMA‐co‐MAH) reached 8 phr, the tensile strength, hardness, and water‐swelling ability of dry‐state WSR exhibited a maximum value and the percentage loss ratio of CPNaAA reached a relatively low value.

Fotofinish: Zink‐substituiertes Cytochrom b562 (Zn‐cyt b562), das an einer Goldelektrode immobilisiert wurde, ist eine Photodiode vom n‐Typ, Zinkcytochrom c (Zn‐cyt c) dagegen ein Photoleiter vom p‐Typ (siehe Bild). DFT‐Rechnungen zeigen, dass die Bandlücken des Cytochroms deutlich kleiner sind als die kleiner Polypeptide. Die Halbleitereigenschaften dieser Proteine hängen von der Ladungsverteilung auf ihrer Moleküloberfläche ab.

No abstract