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Surface segregation behavior in miscible polymer blend thin film of poly(4-trimethylsilylstyrene)(PT)/polyisoprene (PI) was investigated as a function of temperatures on the basis of contact angle and neutron reflectivity measurements. For all temperatures employed, PT, which is a lower surface free energy component, is segregated at the surface of the blend film due to the requirement for minimizing the total free energy of the system. A concentration profile near the blend film surface is in good agreement with the mean-field prediction at 373 K and 393 K, being much lower than the lower critical solution temperature (LCST) for the blend in bulk. It was confirmed that decay length, ξ, and surface excess amount, z*, increase with increasing temperature. On the other hand, a concentration fluctuation in the internal region becomes remarkable at 453 K, even below the LCST in bulk. Thus, it is concluded that a concentration fluctuation in PT/PI blend thin film below the LCST is induced by the surface segregation of PT component in blend thin film.

The phase behavior of the newly found miscible polymer blends poly(4-trimethylsilylstyrene) and polyisoprene was investigated with optical microscopy (OM) and also with differential scanning calorimetry (DSC), while the degree of polymer−polymer interaction was evaluated with small-angle neutron scattering (SANS). The blends with homogeneous one phase at various compositions turned into two phases by heating, showing a lower critical solution temperature (LCST) type phase diagram with a critical temperature of 172 °C if the degree of polymerization is ca. 370. The blend gave a single glass transition temperature below the LCST, and the interaction parameter χ was represented as a function of temperature T according to the relationship χ = 0.027 − 9.5/T.

Three poly(4-trimethylsilylstyrene)-block-polyisoprenes (TIs), the molecular weights of which were 82,000, 152,000 and 291,000 (TI-82K, TI-152K, and TI-291K), were synthesized by sequential anionic polymerizations. The component polymers were a miscible pair that presented a lower critical solution temperature phase diagram if blended. The TI phase behavior was investigated with transmission electron microscopy. The order-disorder transition could be observed at a temperature between 200 °C (the ordered state) and 150 °C (the disordered state) for the block copolymer TI-152K. The block copolymer TI-82K presented the disordered state at 200 °C, whereas TI-291K was in the ordered state at 150 °C. With the Flory-Huggins interaction parameter between poly(4-trimethylsilylstyrene) and polyisoprene, which was evaluated by small-angle neutron scattering for the block copolymers, the TI phase behavior could be reasonably explained by mean-field theory.

Compositional profiles of bilayer films in the direction normal to the interfaces have been investigated by neutron reflectivity measurements and analyzed with mean field theory. The bilayer films were prepared with poly(4-trimethylsilylstyrene) (PTMSS) and polyisoprene (PI), which constitute a miscible polymer pair and whose blends show phase separation at the lower critical solution temperature (LCST) by heating. Because we can accurately control the degree of polymerization of component polymers and can adjust the Flory-Huggins interaction parameter, X, with the temperature, T, according to the relationship X = 0.027-9.5/T, the phase behavior and the interfacial structure of PTMSS and PI are predictable by mean field theory. When the bilayer films of PTMSS and PI were set at 90 C, which is a temperature below the LCST, diffusion at the interface was observed, and the original interface disappeared in several hours; this supports the idea that the polymer pair is miscible. No clear interfaces were identified below the LCST, whereas broad interfaces, compared with that of the strong segregation pairs, were observed above the LCST. The compositions of each layer are consistent with that of the coexisting phase in the polymer blends, and the interfacial widths agree well with the theoretical prediction considering the effect of capillary waves. In addition, all annealed films have a thin surface layer of PTMSS corresponding to surface segregation induced by the lower surface energy of PTMSS (with respect to that of PI). Thus, the interfacial profiles of PTMSS/PI bilayer films have been totally prospected in the framework of mean field theory.

Monodisperse poly(4-timethylsilylstyrene)s (PTMSS's) and the partially deuterium-labeled polymers were prepared and characterized to determine their unperturbed dimensions hy measuring small-angle neutron scattering of their blends. For polymer pairs with three different molecular weight (M w ), the radii of gyration (R g ) in bulk were estimated and a power law was deduced as R g = 0.022M w 0.50 (nm). The power index 0.50 was consistent with the theoretical prediction for ideal chains, 1/2. Although the prefactor, 0.022, is apparently smaller than that of polystyrene (PS), 0.0275, the segment length of this polymer, 0.72 nm, is similar to that of PS, 0.69 nm. It is indicated that the bulky trimethylsilyl group on 4-position does not affect much on the chain conformation of polystyrene hackbone.

A rapid and sensitive method for the quantitation of valproic acid in tears has been developed using gas chromatography/electron capture negative chemical ionization/mass spectrometry. Valproic acid was converted directly into its pentafluorobenzyl ester derivative without the need to perform any extraction from the biologic fluid. The concentrations in tears [C]t correlated very well with those of the free form in the plasma [Cf]p and those of the total form in the plasma [Cb+f]p. The ratios between valproic acid concentrations in tears and plasma were as follows: [C]t/[Cb+f]p = 0.10 +/- 0.02; [C]t/[Cf]p = 0.57 +/- 0.11. Ratios of [C]t/[Cb+f]p were in good agreement with previously published data.

The concentrations of sodium valproate (VPA) in tear and plasma by a quadrapole ion trap type GC/MS (GCQ) in a negative ion/chemical ionization/electroncapture mode. VPA was converted into the pentafluorobenzyl ester and was quantified by monitoring the ion of m/z 143. The VPA concentrations [C]Ts in the tear obtained from patients by non-invasive Schirmer method correlated very well with those of the unbound form in the plasma, indicating that the [C]TS will be used as a convenient index for monitoring the unbound VPA level in the patients.

The two-dimensional (2D) photonic band gap was observed in naturally formed anodic porous alumina. Anodizing of Al under appropriate conditions yielded the anodic porous alumina which had an ordered air-hole array with a multidomain triangular lattice. The transmission spectra of the multidomain triangular air-hole lattice of the anodic porous alumina showed a clear dip in transmission that corresponded to the 2D photonic band gap. The band gap properties of the polycrystalline-type air-hole lattice could be interpreted as being the sum of those for the single-crystalline-type air-hole arrays of anodic porous alumina prepared by an artificial process.

Two-dimensional (2D) photonic crystals were fabricated using anodic porous alumina with a highly ordered air-hole array of triangular lattice with a high aspect ratio of over 200. The transmission properties of the obtained ordered air-hole array in the alumina matrix exhibited a stop band in the spectrum which corresponds to the band gap in 2D photonic crystals.

Two-dimensional (2D) photonic crystals in the visible wavelength region were fabricated using anodic porous alumina with a highly ordered hole array configuration. The transmission properties of an ordered triangular array of an air cylinders with high aspect ratio in alumina matrix showed a stop band in the spectrum which corresponds to the band gap in the 2D photonic crystals.