Electrochemical catalysis and thermal stability characterization of laccase-carbon nanotubes-ionic liquid nanocomposite modified graphite electrode

The hydrophobic carbon nanotubes-ionic liquid (CNTs-IL) get forms a stable modified film on hydrophobic graphite electrode surface. Laccase immobilized on the CNTs-IL gel film modified electrode shows good thermal stability and enhanced electrochemical catalytic ability. The optimal bioactivity occurs with increasing temperature and this optimum is 20 degrees C higher in comparison to free laccase. The improvement of laccase thermal stability may be due to the microenvironment of hydrophobic CNTs-IL gel on graphite electrode surface. On the other hand, the sensitive detection of oxygen has been achieved due to the feasibility of oxygen reduction by both of laccase and nanocomposite of CNTs-IL gel. Furthermore, the laccase hybrid nanocomposite also shows the fast electrochemical response and high sensitivity to the inhibitors of halide ions with the approximate IC50 of 0.01, 4.2 and 87.5 mM for the fluoride, chloride and bromide ions, respectively. It implies the feasibility of laccase modified electrode as an inhibition biosensor to detect the modulators of laccase.

Oriented growth and luminescence of ZnO : Eu films prepared by sol-gel process

A series of Eu3+-doped ZnO films have been prepared by a sol-gel method. These films were characterized by X-ray diffraction (XRD) and photoluminecent spectra (PL). Effects of synthetic parameters, such as annealing atmosphere, temperature and concentration of doped ions, on the highly oriented crystal growth were studied in detail. The crystalline structures of films annealed in vacuum have a wurtzite symmetry with highly c-axis orientation. A characteristic D-5(0) -> F-7(J)(J = 1, 2, 3 and 4) red emission is observed due to energy transfer from the ZnO host to the doped Eu3+ in the c-oriented ZnO films.

Highly oriented tunable wrinkling in polymer bilayer films confined with a soft mold induced by water vapor

The authors report the formation of highly oriented wrinkling on the surface of the bilayer [polystyrene (PS)/poly(vinyl pyrrolidone) (PVP)] confined by a polydimethylsiloxane (PDMS) mold in a water vapor environment. When PVP is subjected to water vapor, the polymer loses its mechanical rigidity and changes to a viscous state, which leads to a dramatic change in Young's modulus. This change generates the amount of strain in the bilayer to induce the wrinkling. With a shape-controlled mold, they can get the ordered wrinkles perfectly perpendicular or leaned 45 S to the channel orientation of the mold because the orientation of the resultant force changes with the process of water diffusion which drives the surface to form the wrinkling. Additionally, they can get much smaller wrinkles than the stripe spacing of PDMS mold about one order. The wrinkle period changes with the power index of about 0.5 for various values of the multiplication product of the film thicknesses of the two layers, namely, lambda similar to (h(PS)h(PVP))(1/2).