The sorption isotherms and transport coefficients for CO₂ in poly (vinyl acetate) (T_g=31°C) film were measured by gravimetric and volumetric sorption methods, and permeation method. Solubility data observed at 45°C from the three methods gave concordant linear sorption isotherms and seemed to obey Henry's law only. Nonlinear isotherms observed at 25 and 15°C were successfully interpreted in terms of the dual-sorption transport model. The two diffusion coefficients, D_eI and D_eE, were obtained using the short-time method and the long-time method for the model of Fickian diffusion, together with the equilibrium solubility (C_e) from the volumetric sorption measurement. The experimental sorption rate curves are initially agreed with the calculated curves using D_eI and the Fickian sorption rate equation, but when the sorption equilibrium is approaching, the curves are in accord with the calculated curves using D_eE. The experimental permeation rate curves initially deviate from the calculated curves using Da and the Fickian permeation rate equation. These observations suggest that some relaxation process is superimposed on the diffusion process. The non-Fickian transport data of both the sorption and permeation were successfully correlated with a model that superimposes diffusion of the Fickian model upon the time-dependent diffusion model. The relaxation phenomena were also observed in PVAc/Ar system at 25°C to 45°C from permeation experiment.

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We reported previously that hydrophobic polymer membranes such as polystyrene and poly-(vinyl chloride) predominantly permeated water from aqueous alcohol solutions. Pervaporation and evapomeation behavior through poly (vinyl p-tert- butyl benzoate) (PVBB) membrane were investigated to clarify further the mechanism of permselectivity for aqueous alcohol solutions through the hydrophobic polymer membranes. The PVBB membrane preferentially permeated water from aqueous alcohol solutions in both the pervaporation and evapomeation, and selectively adsorbed alcohols. This result was explained on the basis that alcohol molecules didn't diffuse so much while water molecules easily diffused through the PVBB membrane, because the former interacted more strongly with PVBB, and the latter had the weaker affinity for PVBB.

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Permeation of four kinds of divalent metal chlorides (CuCl₂, NiCl₂, CoCl₂, CaCl₂) through charged poly (4-vinylpyridine-co-acrylonitrile) membranes with varying degrees of 4-vinylpyridine (4VP) contents (91, 83, 73, 20 mol %) were measured at 25 and 40°C for different upstream salt concentrations (0.01 and 0.02 M or 0.1 and 1 M). It was found that a permselectivity, P (CuCl₂)/P(CaCl₂), was variable from 0.11 to 1800 depending on the 4VP density, temperature, and the salt concentration. Effects of these three factors on permeation, diffusion and partition of the salts were discussed in relation to the stability of metal/4VP complexes formed in the membranes.

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An L-glutamic acid-containing polypeptide with long alkyl side chains, poly(N^ω-stearyl L-glutamine-co-L-glutamic acid) containing 14 mol% of N^ω-stearyl L-glutamine (SG/GA), was prepared. The SG/GA was immobilized onto the surface of a vesicle of dipalmitoylphosphatidylcholine (DPPC) by hydrophobic interaction between the stearyl groups of SG/GA and the hydrophobic region of the vesicle membrane. On the vericle membrane, the SG/GA could interact with added Cu²⁺ ions to form complexes. The complex formation induced changes in the backbone structure of the polypeptide, i.e., the stabilization of α-helical structure. An SG/GA-DPPC composite membrane was prepared by the formation of DPPC multi layer on both sides of a porous support membrane and the SG/GA coating on one face of the multilayer. It was found that Cu²⁺ ions induced a generation of the membrane potential across an SG/GA-DPPC composite membrane prepared. The induced membrane potential could be ascribed to the fixation of Cu²⁺ ion on the membrane, i.e., an increase in the fixed charge density of the membrane, via the SG/GA-Cu (II) complexation on the composite membrane surface.

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Lipase derived from Rhizopus delemar was entrapped in the silk fibroin membrane with the methanol-immersion treatment for 10 min. No leakage of the immobilized enzyme was detected by the method using the enzymatic assay. Thermal effect on the activity of immobilized lipase was studied in detail. The optimum temperature for immobilized enzyme (50°C) was higher than that for the free one (20°C). The lipase was much stabilized by the immobilization with silk fibroin since the inactivation constant, which was determined from the measurement of inactivation process at 50°C, was less than 1/40 of that of the free enzyme. The optimum pH shifted to alkaline side as compared to that of the free one. On the basis of several properties concerning the immobilized lipase and dissolubilization state of the substrate, tributyrin, observed by ¹³C NMR measurement, it was concluded that origin of the stabilization of lipase with silk fibroin was mainly the formation of the unique structure such as Silk II type crystalline in the silk membrane. The lipase-immobilized silk fibroin membrane generated membrane potential with the immobilized-enzyme reaction in the membrane.

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The chemical composition of plasma-polymerized acrylonitrile, especially the structures of the nitrogen-containing moieties, was investigated by means of XPS and IR spectroscopy. The course of plasma polymerization of acrylonitrile was controlled by the W/FM parameter. The polymer deposition rate decreased with the increase in W/FM value from 300 to 1000MJ/kg. The plasma polymers prepared at W/FM values between 300 and 750MJ/kg had N/C atomic ratios of 0.22-0.29, which were lower than that of polyacrylonitrile polymerized conventionally (0.33), and O/C atomic ratios of 0.10-0.15. The inspection of XPS and IR spectra revealed that the plasma-polymerized acrylonitrile was composed of hydrocarbon chains with variety of nitrogen-containing moieties involving amino, amido, cyano, and imino groups in addition to CH₂-CH(CN) repeating units. The treatment of the plasma polymers with dilute hydrochloric acid distinguished amino and amido groups from cyano and imino groups. The complexity of nitrogen-containing moieties is considered to be due to the fragmentation of acrylonitrile molecules in the glow discharge state.

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A new alignment method for liquid crystals was studied. A uniform alignment was obtained by the deposition of a polyimide film spread on the water surface on a glass substrate without rubbing process. The orientation of polymer chains was effected by stretching on the water surface. When the removal velocity of the film was higher, the alignment of polymer chains became higher, and the alignment quality of liquid crystal molecules became better. Even when the main chain of the polymer molecule was not linear, the higher ordering of the liquid crystal molecules was achieved.

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Stereoisomers of tartaric acid derivatives having two long alkyl chains were synthesized. The surface pressure-area isotherms for these compounds were investigated and preparation of Langmuir-Blodgett films was carried out. d- And meso-ditetradecanoyl tartaric acids formed stable monolayers on aqueous CdCl₂. The molecular areas for d- and meso isomers were 48Ų and 43Ų, respectively. These monolayers could be deposited onto a substrate, forming a Z-type film from d-isomer and a Y-type film from meso isomer. Thus, the monolayer-forming behaviour and the properties of Langmuir-Blodgett film are different in each isomer, reflecting the difference in their configurations.

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