The technical skill is explained in the XPS analysis of polymeric material surfaces with regard to measuring the topsurface of several nm in thickness. The difference in elemental composition between the surface and the bulk was detected in a different way using mold of molten resin, organic-solvent cast-film, aqueous cast-film and surface-modified film as samples. The mechanism of the difference is considered. It was confirmed that the surface composition might change depending upon the forming conditions during and after the processing. The analyses of the interface inseparable into two surfaces, surface contamination, surface functionals and chemical structure of surface molecules are also described.
Novel methods for the characterization of polymer surface structure and surface molecular motion have been presented. Scanning viscoelasticity microscopy (SVM) was used in the studies of the surface mechanical properties of polymeric solids. Employing dynamic secondary ion mass spectroscopy (DSIMS) for the depth profiling of the chemical composition of end-labeled polystyrene (PS) film, the end group segregation at the air/solid PS interface was verified. It was revealed that the molecular motion at the surface of glassy polystyrene (PS) was fairly activated, compared with that of bulk one due to the surface segregation of chain end groups. These results indicate that surface glass transition temperature is depressed due to the increase in free volume near surface region. Temperature dependent X-ray photoelectron spectroscopy (TDXPS) was utilized for the characterization of surface molecular motion of symmetric diblock copolymers. The activation of molecular motion at the surface was also confirmed by TDXPS. The two-dimensional mapping of the surface mechanical properties for the polymer blend ultrathin films was carried out on a nanometer scale by using SVM. Composition profile along the thickness direction of polymer blend thin film was also evaluated on the basis of neutron reflectivity (NR).
Epitaxial growth of polymers during solution polymerization of monomers (Polymerization-Induced Epitaxy, PIE) is described. In particular, we report on the observations that (1) PIE can be induced by many kinds of polymerization reactions, (2) PIE occurs even on entropically driven reaction, and (3) anchoring of an amorphous polymer segment by PIE of block copolymer. Finally, we introduce a positive feedback model between polymerization reaction and epitaxial adsorption to explain the PIE mechanism.
Polymer surface modification using plasmas and excimer lasers was introduced, and the essential chemical reactions occurring in the surface modification process were described. The main chemical reactions in surface modification by plasma irradiation are hydrogen abstraction from polymer chains to form carbon radicals at the polymer chain and recombination between the carbon radicals and other radicals in the plasma to form functional groups. Therefore, the easier the hydrogen abstraction from polymers is, the more effective the surface modification. Surface modification by excimer lasers also proceeds with similar chemical reactions, hydrogen abstraction and recombination of carbon radicals with other radicals in the plasma. A new surface modification technique, remote plasma treatment, was proposed and applied for hydrophilic surface modification of poly (tetrafluoroethylene).
This article reviews non-linear macroscopic pattern formation on polymer film surfaces. As a result of solvent evaporation from a dilute polymer solution heated from below, the free surface of the as-cast polymer film undulates and exhibits a two-dimensional pattern due to the undulation. For an ordinary polymer, a hexagonal (or polygonal) pattern was obtained. This pattern, due to surface undulation, was found to be ascribed to convection existing in the solution. On the other hand, a very peculiar concentric-ring pattern was observed for an SBS film, where SBS designates polystyrene-block-polybutadiene-block-polystyrene triblock copolymers. Note that this sample forms lamellar microdomain structures with a ca. 22 nm identity period. In this pattern, a set of concentric rings contained in a cellular compartment is a unit constituent and was found to be a set of wrinkles on the surface. The mechanism of formation of the concentricring pattern is presented in this article, and moreover, control of the morphology of the pattern is discussed.
In order to establish a design technology for ultrahigh-purity gas piping systems and to implement effective purging for future ultralarge-scale integration (ULSI) fabrication lines, it is necessary to develop highly accurate simulation technology. We have investigated the heat of adsorption and adsorption isotherms with trace moisture concentrations on various stainless steel surfaces as a means to develop highly accurate simulation technology. We observed that the activation energy of desorption varied as of the surface coverage ratio of moisture increased in the range under monolayer adsorption. We investigated the vibration cycle of adsorbed moisture molecules, and observed that the vibration cycle was 2×10-13s at the adsorbed moisture concentration of 1.4×1014 molecules/cm2 for an Fe2O3 surface. The calculated moisture concentration using the Freundlich adsorption isotherm coincided with the measured concentration in the range of about two orders of magnitude as compared to other adsorption isotherms.
Surface hydrogen on the growing films of amorphous semiconductors (typically a-Si: H) is monitored in-situ by polarization mondulated infrared reflectance spectroscopy with isotope exchange technique. Thermal desorption of surface hydrogen is observed above 300°C and discussed in relation to the film growth mechanism.
RHEED and its intensity oscillation are widely used for monitoring and controlling the growth by molecular beam epitaxy (MBE). We have discussed that the intensity oscillation is related to either the interference effect between two consecutive layers, surface step density or atomic density on a surface, depending on the diffraction conditions, i.e. the incident energy and the angle. We have also shown a result of multiple scattering calculation from large super-cells obtained by a MBE growth simulation, which should be important for more quantitative analysis of the intensity oscillation.