In this study, multi-walled carbon nanotubes were used as a carbon support. The support for the Pt catalyst was prepared by a convenient technique without the need for acid or heat treatment. Two different preparation methods utilizing a nanocolloidal solution were developed; i. e., method 1 and method 2, an improved method 1. In method 2, the colloidal solution was prepared by first adding the carbon. Based on the SEM and TEM observations, the Pt nanoparticles (5-20 nm) were adequately supported. It was found that the Pt nanoparticles were better supported by the high dispersion in method 2 compared to method 1. The Pt amounts in the Pt/MWCNT catalysts were 31.4 wt. % and 45.9 wt. % when using methods 1 and 2, respectively, based on the ICP-MS measurements. The peaks belonging to the Pt metal were confirmed by XRD measurements. The Pt specific surface area of the Pt/MWCNT calculated by the cyclic voltammetry (CV) measurement results was greater than that of the commercially available Pt/Ketjen catalyst.
This paper describes effects of micro-square-shaped pillar array structures and chemical modification by SF6 or O2 plasma irradiation on wetting properties of SU-8 (photosensitive epoxy resin) for water. Contact angles were measured and microscopic observation of water droplet contours were conducted through the bottom of the glass substrate. For the SU-8 surfaces without chemical modification, Wenzel mode wetting occurred constantly. However, because of the pinning effect, the contact angles on surfaces with micro structures were larger than the values calculated based on the Wenzel mode wetting. The SU-8 surfaces modified by SF6 plasma showed Cassie mode wetting generally and remarkable hydrophobicity with large contact angles of more than 150 deg. The surface became super-hydrophilic after O2 plasma modification.
The surface morphology and mass of a silver coating deposited on a glass substrate using silver mirror coating method were investigated as a function of the bath temperature, the glucose concentration used in the plating bath as a reducing agent, and the coating time necessary to obtain good coating quality. Using the optimum coating conditions of 10.8 ks deposition time and 0.2 °C temperature of the plating bath composed of 0.2 mol dm−3[Ag(NH3)2]++0.12 mol dm−3 glucose, a smooth and uniform silver coating with ca. 150 nm thickness was obtained. Improved adhesion of the silver coat to the glass substrate was obtained by application of an etching pretreatment to the glass substrate using various etchants. A commercially available etchant containing (NH4)HF2 provides an especially strong anchor effect because it induces a considerably rough dissolution trace to the glass substrate.