Improvement of wettability and detergency of polymeric materials by excimer UV treatment

The 172 nm ultraviolet (UV) excimer light was exposed to polyethylene (PE), polypropylene, poly(ethylene terephthalate) and nylon 6 surfaces in ambient air. Changes in the contact angle and particle deposition in liquid due to UV treatment were investigated from the viewpoints of wettability and detergency. For all polymers, the wettability and the acid-base component of the surface free energy evaluated by the contact angle measurements increased remarkably by UV treatment of 1 min. From surface analyses of the polymer surfaces by X-ray photoelectron spectroscopy and atomic force microscopy, oxygen concentration was found to increase after UV treatment, whereas little topographical change was observed. The deposition of PE and nylon 12 particles onto the polymer surface was examined, in situ, in water, water/ethanol mixture, ethanol and n-heptane. Although the number of deposited particles was largely dependent on the kinds of the particle, the substrate and the liquid, a significant decrease in the deposition due to UV treatment was confirmed in any system.     

Synthesis of Pederic Acid and Related Model Studies

{[2‐(Trimethylsilyl)ethoxy]methyl} (SEM)‐protected pederic acid 16 was prepared by deriving the stereogenic center at C(7) from mannitol and those at C(2) and C(3) (mycalamide numbering) from trans‐2,3‐dimethyloxirane. Routes to pederamides involving a late oxygenation at C(7) were explored.     

Photo- and thermal-diffusions of metals into As2S3 glass

Photo- and thermal-diffusion effects of Ag and Cu into As₂S₃ bulk glass have been studied. It has been clarified that the photo-diffusion process is attributed to a purely optical effect. Some differences in diffusing process between Ag and Cu have been clearly shown both for the photo- and thermal-diffusions.     

Electronic structure of C84 and KxC84: Comparison to C60 and graphite

X ray photoemission spectra show ～10 valence band features in C₆₀ and C₈₄ films, although they are less distinct in C₈₄ because of the increased number of valence electrons and the decreased molecular symmetry. The presence of inequivalent carbon atoms in C₈₄ is reflected by the fact that the C 1s main line is ～0.2 eV wider than in C₆₀. The C 1s satellite region of C₈₄ exhibits four features within 15 eV of the main line and shows that the HOMO-LUMO π-π* excitation energy of C₈₄ is ～0.5 eV smaller than in C₆₀. Potassium 2p spectra for K-doped C₈₄ films suggest the formation of a phase with composition K₃C₈₄ with two spectroscopically-distinguishable K sites. A new spectral feature emerges when the K content is increased beyond K₃C₈₄, suggesting a phase transition and a saturated composition of K₆C₈₄, as for K_xC₆₀. These similarities are intriguing since K_xC₈₄ is insulating for all x while K₃C₆₀ is metallic and superconducting.     

Observation of shocked and unshocked BaZnGeO4 by means of electron microscopy

Electron microscopic observations were performed on shocked and unshocked BaZnGeO₄ (BZG). Particular attention was given to the superlattice relation. A specimen shocked to the pressure range of 19–27 GPa, showed a small distortion from the original hexagonal lattice, to an orthorhombic symmetry. Along with this distortion, weak superlattice reflections along the $\text{c1}$ direction in the unshocked BZG were found to disappear completely, while the repetition mode of superlattice reflections along the $\text{b1}$ direction ([110]1 direction in the hexagonal structure) as found to change from three to six, and then to four, with increasing shock pressure. A single crystal—single crystal transition, on a submicrometer scale, was shown to occur due to a small displacement of atoms during shock process.