An investigation of laser microprobe mass spectrometry (LAMMS) for polymer surface treatment and its inhomogeneity

Laser microprobe mass spectrometry was applied for the detection of inhomogeneity of the polycarbonate surface treated with silane coupling agent. Clear difference in spectrum patterns between the treatments with and without a non-ionic fluorocarbon surfactant was observed. The chemical bonds between silicon/zirconium and carbon have been confirmed to generate only in the presence of the surfactant which participates in homogenization of the surface.     

Proton momentum spectra in high-energy reactions of 9Be and 12C with quasimonochromatic photons

Momentum spectra of protons emitted at three lab angles 23°, 55° and 130° in high-energy photoreactions of ⁹Be and ¹²C are studied by using tagged photons in the energy range between 360 and 600 MeV. At 23° and 55°, we observe a structure which may be ascribed to protons from quasifree production of a single pion and those from quasideuteron photodisintegration, while at 130°, the spectra are predominantly due to protons resulting from intranuclear multiple scattering. The results of an intranuclear cascade calculation are compared with the data.     

Multiple photofragmentation pathways with different recoil anisotropy from a metal-ion-ligand complex

Spatial recoil anisotropy that is dependent upon the fragment-ion species is reported for the first time for a metal-ion-ligand complex after a single photoexcitation process by linearly polarized light. Upon excitation to the lowest three excited states of Mg+-ICH3, originating from the Mg+2P states, fragment ions of MgI+ and ICH+3 are found to have clear and different angular dependences, which are also characteristic of the excited states. These are explained from the results of theoretical work in that the calculated ground-state complex has a bent structure and further in that each transition dipole moment vector of the complex almost coincides with the Mg+ 3p orbital lobe direction in each case. The fragment ions are concluded to be formed along dissociative potential surfaces which are crossed by the initially excited states, in a much faster process than the rotational period of the complex.     

Novel polyene dyes for highly efficient dye-sensitized solar cells

We have developed an efficient and novel polyene-dye-sensitized nanocrystalline TiO2 solar cells producing a 6.8% solar energy-to-electricity conversion efficiency (eta) under AM 1.5 irradiation (100 mW cm(-2)): short-circuit current density (Jsc), 12.9 mA cm(-2), open-circuit photovoltage (Voc), 0.71 V, fill factor (ff), 0.74.     

Silica coating of silver nanoparticles using a modified Stober method

Silver nanoparticles prepared through a borohydride-reduction method were directly coated with silica by means of a seeded polymerization technique based on the Stober method. Various amine catalysts were used for initialization of a sol-gel reaction of TEOS with no need for a prior surface modification. Use of dimethylamine (DMA) as a catalyst was found to be necessary to obtain a proper coating. The silica shell thickness was varied from 28 to 76 nm for TEOS concentrations of 1-15 mM at 11.1 M water and 0.8 M DMA. The optical spectra of the core-shell silver-silica composite particles show a qualitative agreement with predictions by Mie theory.     

In situ observation of phase separation processes in gelling alkoxy-derived silica system by light scattering method

The investigation of phase separation processes induced by polymerization reactions of tetramethoxysilane (TMOS) was attempted by a time-resolved light scattering method for TMOS-formamide-water system under the acid-catalyzed condition. Since the early stage of the phase separation exhibits very fast kinetics and weak scattering intensity, the experimental set-up was designed so as to reduce the experimental error and to obtain higher time resolution by using a laser beam expander. For the gels whose morphologies are interconnected structure and aggregates of particles, it was experimentally found that the wavelength of the concentration fluctuation in the early stage of phase separation was time-independent and its amplitude grew exponentially with time. This suggests that these samples phase-separate by spinodal decomposition mechanism. In the later stages of phase separation, the coarsening process and the following structure-freezing process by gel-network formation were observed.