Emulsions Stabilized with Polyelectrolyte Complexes Prepared from a Mixture of a Weak and a Strong Polyelectrolyte.

The possibility of stabilizing emulsions with polyelectrolyte complexes (PEC) obtained from the interaction of two non-surface-active oppositely charged polyelectrolytes (PEL) is described. Poly(allylamine hydrochloride) (PAH) and poly(4-styrene sulfonate) sodium salt are selected as the weak cationic and the strong anionic polyelectrolyte, respectively. Aqueous polymer mixtures are investigated by light scattering to determine the size of the complexes and whether precipitation or complex coacervation occurs.

Emulsion stabilisation by complexes of oppositely charged synthetic polyelectrolytes.

We investigate the possibility of stabilising oil-water emulsions from the polyelectrolyte complexes (PEC) obtained in mixtures of a strong cationic polyelectrolyte (poly(diallyldimethylammonium chloride), PDADMAC) and a weak anionic one (poly(acrylic acid)sodium salt, PAANa). Unlike other previous work however, both polyelectrolytes (PEL) are chosen as they are completely water-soluble and possess no surface activity when present alone over nearly all the pH range. In water, the effects of PEL concentration, PEL mixing ratio and pH on the formation of PEC are studied in detail.

Novel stabilisation of emulsions by soft particles: polyelectrolyte complexes.

We put forward the concept of a novel particle stabiliser of oil-water emulsions, being the polyelectrolyte complex (PEC) formed between oppositely charged water-soluble polymers in cases where either polymer alone is incapable of stabilising an emulsion. Using poly(4-styrene sulfonate) sodium salt, PSSNa and poly(diallyldimethylammonium chloride), PDADMAC, of low polydispersity and similar molecular mass, we correlate the behaviour of their mixtures in water with that of emulsions after addition of oil. In aqueous mixtures, spherical particles of diameters between 100 and 150 nm are formed through electrostatic interactions between charged polymer chains.

A macroscopic reaction: direct covalent bond formation between materials using a Suzuki-Miyaura cross-coupling reaction.

Cross-coupling reactions are important to form C-C covalent bonds using metal catalysts. Although many different cross-coupling reactions have been developed and applied to synthesize complex molecules or polymers (macromolecules), if cross-coupling reactions are realized in the macroscopic real world, the scope of materials should be dramatically broadened. Here, Suzuki-Miyaura coupling reactions are realized between macroscopic objects.

Supramolecular adhesives to hard surfaces: adhesion between host hydrogels and guest glass substrates through molecular recognition.

Supramolecular materials based on host-guest interactions should exhibit high selectivity and external stimuli-responsiveness. Among various stimuli, redox and photo stimuli are useful for its wide application. An external stimuli-responsive adhesive system between CD host-gels (CD gels) and guest molecules modified glass substrates (guest Sub) is focused.

Dry oil powders and oil foams stabilised by fluorinated clay platelet particles.

A series of platelet sericite particles coated to different extents with a fluorinating agent has been characterised and their behaviour in mixtures with air and oil studied. The material which forms by vigorous shaking depends on both the surface tension of the oil and the surface energy of the particles which control their degree of wetting. Oil dispersions are formed in liquids of relatively low tension (<22 mN m(-1)), e.

Pulsed-field gradient NMR measurements on hydrogels from phosphocholine.

Gels from diacylphosphatidylcholine in glycerol/butylene glycol mixtures were investigated by pulsed-field gradient NMR measurements. Previous measurements had shown that the gels are formed by networks from crystalline multilamellar vesicles (MLV). The obtained self-diffusion coefficients for water and butylene glycol molecules indicate that both molecules occur in two different environments, even at temperatures above the phase transition T(m) where the system is still in a liquid crystalline state.

Desensitization of feedback inhibition of the Saccharomyces cerevisiae gamma-glutamyl kinase enhances proline accumulation and freezing tolerance.

In response to osmotic stress, proline is accumulated in many bacterial and plant cells as an osmoprotectant. The yeast Saccharomyces cerevisiae induces trehalose or glycerol synthesis but does not increase intracellular proline levels during various stresses. Using a proline-accumulating mutant, we previously found that proline protects yeast cells from damage by freezing, oxidative, or ethanol stress.

The production of recombinant APRP, an alkaline protease derived from Bacillus pumilus TYO-67, by in vitro refolding of pro-enzyme fixed on a solid surface.

Bacillus pumilus TYO-67 has been isolated from tofuyo, a traditional fermented food made from soybean milk in Okinawa, Japan. This bacterium secretes a soybean-milk-coagulating enzyme (SMCE), which can be applied for the production of processed foods from soybean milk. Thus, an easy method of producing the recombinant enzyme was developed in this study.