Motoo Akagi

Polymer adsorption on a magnetic particle in a dispersion system

Abstract A magnetic particle dispersion was prepared by mixing the magnetic γ - Fe 2 O 3 particles or barium-ferrite particles and epoxy resin with solvent. The relationship between the mixing conditions and the adsorbed amount of the epoxy resin on the particle surface was investigated. It became clear that the polymer adsorption occurring during the mixing process required both large mechanical shear and high temperature. The large mechanical shear was necessary to break the coagulation of the particles and high temperature was necessary to cause chemical reaction between the polymer and the particle surface. The adsorbed polymer improved dispersibility of the particles in the dispersion, which was confirmed by transmission electron micrograph, viscosity measurement and surface roughness measurement of the coated films made from the dispersions.

Electron micrographs of hologram cross sections

The cross sections of both amplitude and phase holograms are observed by electron microscopy. Holograms were recorded on Kodak 649F and Scientia 14C75 sheet films by using a He–Ne laser beam (6328 A). It is shown that the holograms are recorded throughout the whole thickness of the emulsion layer and the developed grains are enlarged by bleaching (about 1.5 times by length). This enlargement can be correlated with the thickness change of the emulsion layer during the chemical processing in making holograms.

Formation of pyrene crystalline thin films assisted by helium ion bombardment

This paper reports on the effect of low energy He+ ion‐beam bombardment upon the structure of pyrene thin films formed on quartz substrates. Films are prepared by vacuum evaporation during ion bombardment at room temperature. The structure of the film is controlled by the kinetic energy and current density of the ions. The colorless and transparent crystalline films preferentially oriented with their {001} plane parallel to the substrates are obtained by bombardment of 350 to 500 eV, 60 nA/cm2 He+ ions. Ion‐beam irradiation of the higher ion current density enhances intermolecular chemical reactions and, as a result, a crystalline polymer with its {001} plane parallel to the substrate is produced.