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Solution plasma (SP), which is a discharge in the liquid phase, has the potential for rapid sterilization of water without chemical agents. The discharge showed a strong sterilization performance against Escherichia coli bacteria. The decimal value (D value) of the reduction time for E. coli by this system with an electrode distance of 1.0 mm was estimated to be approximately 1.0 min. Our discharge system in the liquid phase caused no physical damage to the E. coli and only a small increase in the temperature of the aqueous solution. The UV light generated by the discharge was an important factor in the sterilization of E. coli.

Hydrophilic modification of polyethylene terephthalate (PET) was successfully demonstrated by surface wave plasma treatment followed by graft polymerization with various monomers such as acrylic acid (AA), (2-hydroxyethyl) methacrylate (HEMA), and styrene (St) in the vapor phase. The plasma treatment did not physically damage the PET surface. The graft reactions were confirmed by water contact angle measurements and X-ray photoelectron spectroscopy (XPS). The water contact angles of the PET surface modified with hydrophilic AA and HEMA monomers decreased from approximately 80° before treatment to less than 35°, and the hydrophilicity of the PET surface modified by hydrophilic AA and HEMA monomers was maintained for 70 h. 3T3 fibroblast cells were cultured on the modified PET surfaces to investigate the bioactivity of the modified PET surfaces.

Thicknesses of films formed on the copper in alkaline solution in the presence of alanine are studied by ellipsometric method. It was found that small additives of β-alanine (10-4-10-3 mol/l) cause additional stabilization of copper passivity due to an increase in the film thickness. The adsorption kinetics of α- and β-alanine is studied. It is shown experimentally that β-alanine adsorbs on copper according to the Frumkin isotherm. By contrast, no definite type isotherm can be obtained for α-alanine due to its higher activity and ability to form soluble complexes with copper ions.