Eishun Tsuchida

Conduction of lithium ions in polyvinylidene fluoride and its derivatives—I

Abstract Polymeric solid electrolytes were prepared from the hybrid of poly(vinylidene fluoride) and lithium perchlorate. These were obtained as films having a thickness of about 0.1 mm, and high lithium ionic conductivity [about 10−5 (S cm−1)] was observed for the hybrid film containing 20 mol% of lithium perchlorate and 30 mol% of propylene carbonate at 40°C. The conductivity depended on the content of lithium perchlorate and additives having high boiling temperature and high dielectric constant. Higher conductivity about 10−5 (S cm−1) could be obtained by setting a suitable composition of these three components, ie, poly(vinylidene fluoride), lithium perchlorate and additives. Lithium perchlorate was observed to be dispersed homogeneously in the hybrid film with suitable composition from X-ray diffraction measurement. However, an excess of the micro salts were incorporated as micro crystals in polymer matrix.

Formation of interpolymer complexes

Abstract Interpolymer complex formations of poly(methacrylic acid) (PMAA) or poly(acrylic acid) (PAA) with oligocations as well as poly(ethylene oxide) (PEO), and poly-(N-vinyl-2-pyrrolidone of various chain lengths were studied. For the case of complexation between PMAA and oligocations, the standard free energy change for the complexation ΔG° was found to be linearly dependent on the number of interacting sites, n. The stability constant K for complex is expressed as K = AeBnwhere A and B are constants which depend on the chemical structure of the polyelectrolytes. For the case of complex formation through hydrogen bonding, the degree of linkage Θ, defined as the ratio of the binding groups to the total of potentially interacting groups, and the stability constant K of the polymer-polymer complexes both in aqueous and aqueous-alcoholic media were determined as a function of temperature by means of potentiometric titration. It was found that Θ and K were strongly dependent on chain length, temperature, a...

1H-NMR Study of the effect of synthetic polymers on the fluidity, transition temperature and fusion of dipalmitoyl phosphatidylcholine small vesicles

The interaction of water-soluble polymers with dipalmitoyl phosphatidylcholine small vesicles and the effect on vesicle fusion were studied by means of 1H-NMR spectrometry. The motion of dipalmitoyl phosphatidylcholine molecules decreased on interaction with the polymers and was detected as a change in the signal intensity. The interaction behavior of polymers is very sensitive to the chemical structure of the applied polymers. Poly(styrene sulfonic acid) and poly(ethylene glycol) decreased the motion of the choline methyl group, predominantly through coulombic and hydrophobic interaction forces, respectively. For example, in the case of the poly(styrene sulfonic acid)-containing system, the signal intensity of the choline methyl group was decreased about 15% while those of the hydrophobic methylene and terminal methyl groups were scarcely decreased by the addition of polymer to a final concentration of 4.0 x 10(-2) unit mol/l. These polymers are considered to interact with the surface of the vesicle membrane. On the other hand, poly(L-glutamic acid) and poly(N-vinyl-2-pyrrolidone) decreased the signal intensities of not only the choline methyl group, but also those of the hydrophobic methylene and terminal methyl groups. This result suggests that part of these polymers might be incorporated into the hydrophobic region of the vesicle membrane. Addition of the non-ionic polymers inhibited vesicle fusion considerably. This effect was explained by the stabilization of dipalmitoyl phosphatidylcholine vesicles by complexation with these polymers.

Fluorescence polarization study on the increase of membrane fluidity of human erythrocyte ghosts induced by synthetic water-soluble polymers

The effect of water-soluble polymers on the membrane fluidity of human erythrocyte ghosts was investigated and was compared with that of concanavalin A by means of the fluorescence polarization technique. 8-Anilino-1-naphthalene sulfonic acid sodium salt and 1,6-diphenyl-1,3,5-hexatriene were used as probe molecules. The membrane fluidity was increased by the addition of polycations with concentrations of less than 2 x 10(-3) wt% 60 min after mixing. The fluidity changes were affected by the chemical structure (hydrophobicity, charge density, etc.) of polycations. Thus, the membrane fluidity increased markedly with increasing charge density on the chain backbone of polycations. On the other hand, nonionic polymers such as poly(ethylene glycol) and poly(N-vinyl-2-pyrrolidone) changed the membrane fluidity in a biphasic manner. That is, the fluidity of human erythrocyte ghost was temporarily increased and then decrease. For example, 20 wt.% of poly(ethylene glycol) gave a maximum fluidity 15 min after mixing with erythrocyte ghosts. A similar fluidity change was observed by adding concanavalin A. Such fluidity changes were not observed when lipid bilayer vesicles were used instead of cell membranes. These results suggested that the increase of membrane fluidity resulted from the intramembraneous aggregation of membrane-bound proteins which was induced by the added polymers. Cell agglutination was also induced by the addition of a large amount of polymers. This agglutination was considered to be due to the intermembraneous aggregation of membrane-bound proteins.

Interaction of human erythrocyte ghosts or liposomes with polyethylene glycol detected by fluorescence polarization

Abstract The membrane fluidity of human erythrocyte ghost was temporarily increased by the addition of polyethylene glycol with molecular weight of 7500. On the other hand, the fluidity of dipalmitoylphosphatidyl choline bilayer liposomes was monotonously decreased by the addition of polyethylene glycol. Fusion of liposomes was inhibited by the interaction with polyethylene glycol. The temporary increase in membrane fluidity of erythrocyte ghosts was considered to be the result of the clustering of membrane-bound proteins which is believed to be one of the most important sequences in cell fusion.

Demonstration of solid-state cell based on poly(vinylidene fluoride) system containing lithium perchlorate

SummaryFlexible film was prepared from poly(vinylidene fluoride) with lithium perchlorate dispersed at molecular level. This film showed lithium ionic conductivity of 10−6 S/cm. A solid-state cell was demonstrated by this film with metallic lithium and Manganese dioxide as electrodes. The cell was stable over a week and it showed electromotive force of 3.0 V and current of 50 μA when 50 kΩ of resistance was connected.