SynopsisDiffusion of a and p cyclodextrin (a-CD and P-CD, respectively) has been studied in aqueous solutions of poly(methacry1ic acid), sodium poly(styrene sulfonate), having three different degrees of sulfonation (DS), and copoly(styrene-methacrylic acid) containing three different amounts of styrene. N-Acetylglucosamine and raffinose were included as reference diffusants. It was found that a decrease of the diffusion coefficients of the CDs in these polymer solutions is characteristically dependent on the polymer concentration, DS, styrene content, and the degree of neutralization. The results were interpreted by assuming a 1:l complex formation between CD and an appropriate residue in the polymer. The complex diffusion behavior of CD in the copolymer solutions suggested that the ability of the polymer residue to form complexes with the CD is lost when the polymer chain dimensions are reduced with decreasing neutralization.

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This paper deals with a procedure to simulate the foaming process of polyurethane integral skin foams. The process involves heat generation by chemical reaction, heat loss through the mold, and local vaporization and condensation of the solvent. To simulate this dynamic process, a boundary mobile cell model was proposed. Each cell contains a certain mass of the solvent. The volume, temperature, and pressure of each cell can be estimated by the quantity of heat which is generated and/or transferred in the cell, assuming that no pressure gradient exists and the total volume of each cell is constant. For a typical polyurethane system, apparent density profiles were predicted theoretically, as well as chemical conversion, temperature, and pressure profiles. Experimental results were compared with the theoretical values. Rather good agreement between them was obtained, though no adjusting parameter was introduced.

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Photochemical vapor deposition technique using an ArF excimer laser has been employed to deposit W films on SiO2 and Si from a WF6 and H2 system. Adhesion characteristics of the film to SiO2 are found to depend both on substrate temperature and on H2/WF6 gas flow ratio: good adhesion is obtained with an increase in the temperature or the ratio. Film formation has reaction orders of 1, 1/2 , and 1 with respect to deposition time, and WF6 and H2 partial pressures, respectively. An activation energy of 0.36 eV is estimated for this film formation on both SiO2 and Si; this energy is plausibly due to H atom diffusion on the W surface. These findings are different from conventional thermal chemical vapor deposition. Film resistivities as low as about 2× the value of bulk W have been observed in the substrate temperature range 250–500 °C. The crystalline structure of the film deposited in this temperature range is uniquely of the α phase. The crystal orientation of the film depends both on substrate temperature and on H2/WF6 gas flow ratio: at low ratios, the dominant crystal orientation varies from (110) to (200) with an increase in temperature. With an increase in H2/WF6 gas flow ratio, the dominant crystal orientation is changed from (200) to (110).