Keiji Tanaka

The film thickness dependence of surface structure for immiscible polystyrene/poly(methyl methacrylate) (PS/PMMA) films was investigated on the basis of atomic force microscopic observation and X-ray photoelectron spectroscopic measurement. In the case of the PS/PMMA film of 25 μm thickness, the air−polymer interfacial region was covered with a PS rich overlayer due to its lower surface free energy compared with that of PMMA and a well-defined macroscopic phase-separated structure was formed in

Surface glass transition temperature, , of monodisperse polystyrene (PS) films was determined from the temperature dependence of lateral force at a given scanning rate. The end groups of the PS were composed of sec-butyl group and a repeating unit terminated by proton. of the PS films was discerned to be markedly lower than its bulk Tg, , in the entire number-average molecular weight, Mn, range, 4.9K to 1460K. The Mn dependence of was analyzed on the basis of a simple power law. The exponent of

ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTMolecular Weight Dependence of Surface Dynamic Viscoelastic Properties for the Monodisperse Polystyrene FilmKeiji Tanaka, Aki Taura, Shou-Ren Ge, Atsushi Takahara, and Tisato KajiyamaView Author Information Department of Chemical Science & Technology, Faculty of Engineering, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-81, JapanCite this: Macromolecules 1996, 29, 8, 3040–3042Publication Date (We

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTUltrathinning-Induced Surface Phase Separation of Polystyrene/Poly(vinyl methyl ether) Blend FilmKeiji Tanaka, Jeong-Sik Yoon, Atsushi Takahara, and Tisato KajiyamaCite this: Macromolecules 1995, 28, 4, 934–938Publication Date (Print):February 1, 1995Publication History Published online1 May 2002Published inissue 1 February 1995https://pubs.acs.org/doi/10.1021/ma00108a021https://doi.org/10.1021/ma00108a021research-articleACS PublicationsRequest reuse p

In order to reduce anomalous leakage current from n-channel polycrystalline-silicon thin-film transistors (poly-Si TFTs), an offset structure that has an n/sup -/ region between channel and n/sup +/ source-drain electrodes has been proposed. Drain-current measurements of the poly-Si TFT prove that the offset structure is effective in reducing the anomalous leakage current, and that the optimization of the offset length and the doping concentration in the offset region enlarge the ON/OFF current

The IEEE 802.3av 10G-EPON Standardization work was completed in September 2009, and 10 Gbit/s Ethernet-based next-generation access is now proceeding to the next stage. We review key features of the IEEE 802.3av Specifications and its research and development status.

Surface molecular motions of monodisperse polystyrene (PS) films, their binary and ternary blend films, and commercially available polydisperse PS films were investigated on the basis of scanning force microscopic (SFM) measurements at 293 K. The monodisperse PSs were synthesized by a living anionic polymerization. The binary and the ternary PS blends were prepared by mixing monodisperse PSs with different molecular weights. The commercially available PSs were used as the polydisperse PS sample.

The segmental mobility of a typical amorphous polymer, polystyrene, at the interfaces with solid substrates was noninvasively examined by fluorescence lifetime measurements using evanescent wave excitation in conjunction with coarse-grained molecular dynamics simulation. The glass transition temperature (T(g)) was discernibly higher at the interface than in the internal bulk region. Measurements at different incident angles of excitation pulses revealed that T(g) became higher closer to the inte

Surface molecular aggregation structure and surface molecular motions of high-molecular-weight polystyrene/low-molecular-weight poly(methyl methacrylate) (HMW-PS/LMW-PMMA) blend films were investigated on the basis of X-ray photoelectron spectroscopic measurements and scanning force microscopic observations. Monodisperse PS with Mn = 1450k, where Mn denotes the number-average molecular-weight, and monodisperse PMMAs with Mn 1.2k, 4.2k, 40.5k, 144k, and 387k were used as HMW-PS and LMW-PMMAs, res

The local conformation of poly(methyl methacrylate) (PMMA) chains at the nitrogen (N2) and water interfaces was studied by infrared-visible sum-frequency generation (SFG) spectroscopy. Although SFG spectra in the C–H region for PMMA at the N2 interface have been hitherto reported, the peak assignments are not in accord with one another. Thus, we first made accurate assignments of SFG peaks using films, which had been well annealed at a temperature above the glass transition temperature for a lon

Density profiles of a perdeuterated poly(methyl methacrylate) (dPMMA) film spin-coated on a substrate in water, hexane, and methanol, which are "nonsolvents" for dPMMA, were examined along the direction normal to the interface by specular neutron reflectivity (NR). The interfaces of dPMMA with the liquids were diffuse in comparison with the pristine interface with air; the interfacial width with water was thicker than that with hexane. Interestingly, in water, the dPMMA film was composed of a sw