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Maekawa, Yasunari; Suzuki, Yasuyuki; Maeyama, Katsuya*; Yonezawa, Noriyuki*; Yoshida, Masaru
Langmuir, 22(6), p.2832 - 2837, 2006/03
Times Cited Count：6 Percentile：30.05(Chemistry, Multidisciplinary)Chemical modification of the internal surfaces of cylindrical pores with sub-micrometer of pore diameter in PET film was examined. The modification involved the alkylation of the carboxylic acid on the surfaces with the alkylation reagent containing a fluorescent probe, and it was monitored by observing the change in fluorescent emission intensity. When the DMF solution of 4-(bromomethyl)-6,7-dimethoxycoumarin (BrCU), which bore a coumarin fluorophore, was introduced into the pores, the emission and excitation intensities of the membranes increased proportionally with increases of the pore surface areas. Fluorescent spots of about 300 nm in diameter, which were located at the positions of the pores, can be observed in the fluorescence microscope image of the membranes, indicating that highly concentrated fluorescent probes are chemically incorporated on the internal surfaces of the cylindrical pores with 210 nm in diameter in the membranes. In the reactions of the PET surfaces with BrCU, the fluorescent intensities increased with increases of the contact angles. This result indicates that the hydrophilicity of the internal pore surfaces can be qualitatively modified by controlling the change in the fluorescent intensities.
Maekawa, Yasunari; Suzuki, Yasuyuki; Maeyama, Katsuya*; Yonezawa, Noriyuki*; Yoshida, Masaru
Chemistry Letters, 33(2), p.150 - 151, 2004/02
Times Cited Count：4 Percentile：21.74(Chemistry, Multidisciplinary)Since well-characterized chemical modification of pore inner surfaces in polymer membranes should be very important from the view point of synthetic chemistry of polymer surfaces as well as designing materials for application such as separation membranes and nanoscopic electronic devices, we reported herein the chemical modification of internal surfaces of the cylindrical pores with 0.31 and 0.54 
m in diameter through the reaction of the carboxylic acids on the surfaces with the alkylation reagent bearing a pyrene fluorophore. The incorporation of the fluorophore on the pore internal surfaces were successfully confirmed by the fluorescence microscope images of the membrane reacting with the alkylation reagent bearing a pyrene fluorophore.
Maekawa, Yasunari; Suzuki, Yasuyuki; Yoshida, Masaru; Maeyama, Katsuya*; Yonezawa, Noriyuki*
Polymer, 44(8), p.2307 - 2312, 2003/04
Times Cited Count：7 Percentile：29.01(Polymer Science)The preparation of ion track membranes of thermally stable polyimide films has been performed by ion beam irradiation of partially imidized polyamic acid (PAA) films followed by alkaline etching and final imidization. No discernible positive hole patterns were observed on the irradiated films of partially imidized PAA containing sulfonyl linkages, although sulfonyl group is known to be highly sensitive to ion beams. In contrast, positive hole patterns appeared on the irradiated films of the partially imidized PAA with 68-89% imidization degrees that contains sulfonyl linkages along with a methylene group in the main chain. The most contrasty hole patterns with 0.3 m diameter were observed on the irradiated PAA films of 89% imidization degree. The irradiated PAA film with the hole patterns was then transformed to the corresponding polyimide film with curing at 350
C for 1 h. From the structural comparison of the polyimides, the possible mechanism for the hole pattern formation is suggested.
Suzuki, Yasuyuki; Maekawa, Yasunari; Yoshida, Masaru; Maeyama, Katsuya*; Yonezawa, Noriyuki*
Chemistry of Materials, 14(10), p.4186 - 4191, 2002/10
Times Cited Count：17 Percentile：53.64(Chemistry, Physical)Dual tone imaging of polyimide films was prepared by Xe ion beam irradiation of partially imidized polyamic acid (PAA) films followed by alkaline etching in aqueous tetramethylammonium hydroxide solution and heating of treated films. In 87% imidized PAA film, ion beam irradiation produced a negative hemispheric structured image with 1.0 mm height and 1.5 mm diameter. In contrast, a positive hole pattern with 0.3 mm diameter appeared on the 82% imidized PAA film. Positive and negative images were considered to be switched by slight change in the balance of scission and crosslinking of the polymer chains, resulting from energy deposition of the ion beam.
Suzuki, Yasuyuki*; Li, J.; Maekawa, Yasunari; Yoshida, Masaru; Maeyama, Katsuya*; Yonezawa, Noriyuki*
Nihon Kagakkai-Shi, 2002(2), p.255 - 259, 2002/02
The hydrophilic surface of poly(ethylene terephthalate) (PET) film, obtained by partial hydrolysis, was converted to hydrophobic one under dry air, saturated water vapor atmosphere, nitrogen, and vacuum at temperatures ranging from 0 to 80C. The hydrophilicity of the surface increased significantly faster under the saturated water vapor although it was the most hydrophilic in the examined conditions. From the dependence of the absolute temperature on the rate of hydrophilicity change for each storage condition, a discontinuous point at ca. 50C was observable only under the water vapor condition. This relation indicates that the appreciable acceleration of the hydrophilicity change on the surface under the hydrophilic condition might be resulted from the increase of the surface mobility due to the water adsorption on the PET surface.
