Hirotaka Hirata

Die Untersuchung der Adsorptionskomplexe von Polymeren mit grenzflächenaktiven Substanzen. III

Zusammenfassung1.Auf die Solubilisation in Lösungen von grenzflächen-aktiven Substanzen wirkt das Zufügen von Polymeren im allgemeinen synergistisch, doch unter Umständen auch antigistisch. Einige Beispiele über den letzten Fall wurden neuerdings gefunden und der Mechanismus diskutiert.2.Der Einfluß von Zusätzen, wie wasserlösliche organische Lösungsmittel oder nicht-ionische grenzflächen-aktive Substanz, auf das Solubilisationsvermögen von ionischen grenzflächen-aktiven Substanzen wird vom Standpunkt der Komplexbildung betrachtet.3.Die verdünnte wässerige Lösung von Poly(propylenglykol) oder Poly(vinylmethyläther) trübt sich von einer bestimmten Temperatur aufwärts. Diese Phasentrennungstemperatur wird durch Zusatz von grenzflächen-aktiven Substanzen erheblich erhöht. Der Mechanismus wurde erklärt.

Electron diffraction observed in the gigantic micelle-producing system of CTAB-aromatic additives

Abstract Single crystals with gigantic rod-like micelles have been found in electron micrographs of a system composed of cetyltrimethylammonium bromide (CTAB) and salicylic acid (SA). The system exhibits a spectacular viscoelasticity in solution. Net-like electron diffraction patterns of the crystals were observed. We deduced that the spots did not result from a component species, CTAB or SA, but arose from the single crystals of, probably, a new species of complexed CTAB/SA.

Novel surfactant species developed in the formation of molecular complex systems: in connection to the theory of “solubilization”

Abstract Series of crystalline surfactant molecular complexes obtained in both ionic surfactant systems of quaternary ammonium and pyridinium salts and alkyl sulfate salts, provided knowledge not only about crystal structure by X-ray analysis but also regarding solution behavior. In solution the surfactant molecular complexes behaved as a novel surfactant species different from the mother; i.e., they presented their own critical micelle concentrations and inherent Krafft points. In addition, observation of the yielding process in crystalline surfactant molecular complexes from homogeneously solubilized solution systems offered significant evidence to reconsider the fundamentals of “solubilization” as the following: that “solubilization” should merely be the dissolution systems of the surfactant complexes that are spontaneously generated in the processes. On the basis of the new ideas it has been clarified that we can always realize promptly any desired solubilized solution system if we have, beforehand, acquired surfactant molecular complexes between the desired surfactant and the solubilizates that are directly insoluble in water.

Material Capture in the Surfactant Solid State

Abstract An interesting behavior of gaseous capture of materials by solid surfactant matrices was examined in comparison with behaviors of other substances (other matrices) which possess long alkyl chain and supposedly similar crystal structure to the surfactant. Through this study it was revealed that the behavior of gaseous capture of materials was characteristic to the surfactant species. Of all surfactants cationic species was conspicuous followed by nonionics, while in anionics the behavior was very poor. Among cationics quaternary and tertiary species especially superior to any other class. For these cationic surfactant species the powder X-ray diffraction measurement disclosed that the gaseous capture of materials remarkably modified matrix surfactant crystal lattices, causing the surfactant molecular complex formation which had already been established by authors.

Enthalpy of formation of crystalline surfactant molecular complexes

Abstract The standard enthalpy of formation of novel chemical species — crystalline cationic surfactant molecular complexes — was studied to elucidate the bonding nature, serially scanning over the different surfactant chain-length homologs and various additive species. The enthalpy was not large, but was obviously dependent on the surfactant chain length and the chemical nature of the additive species. The typical complexes comprising long alkyl chain surfactants were formed endothermally, while in short alkyl chain homologs the process was exothermic. By examining the thermal aspect, it was suggested that the typical complexes of long alkyl-chain surfactants were derived not from attractive energetic force factors, but rather from entropic factors associated with the occurrence of severe disorder caused by heavy thermal agitation in the complex crystalline state.

Excellently guarded materials against UV and oxygen in the surfactant molecular complex crystal matrix

Crystalline surfactant molecular complexes (SCMs) generated between quaternary ammonium cationic surfactants such as CTAB and various additives disclose their excellent protective properties from UV light and oxygen to complex additive materials, which are occluded in the complex crystal matrix. The effects of UV and oxygen were followed by the absorption decay of additive chromophores in comparing that of naked additive specimens with that of those in the complexed state. From the decay profiles, the rate constants and the half-life times were estimated under the assumptions in which the photo and oxidation processes were dominated in accordance with the first-ordered reaction. The results afford us promising prospects in extending the shelf-life of every material, above all medicinal drug, with the consequence that these obtained values evidently demonstrate the remarkably suppressed rate and extremely elongated half-life times.

A model of biological growth

SummaryWhen a piece of flat aluminium foil is pricked by a needle in allyl chloride-toluene solution, a red colored spot appears there instantly. On the red spot, a light yellow sheath-like product grows continuously at the rate of about 3 cm/hr. Since the product is composed of polymers and has the definite growth point like the bud of the plant, the growth might be regarded as more well fitting model of biological growth than the models ever known (e. g. Traubes artificial cell and chemical or flower gardens). When a line is drawn by a knife on the foil in the solution, the color of the line instantly changes to red, and a thin plate-like product grows on the red line. Thus any letter can be written at will with a knife on aluminium foil as with a red pencil on white paper. And then, on the red letter, a light-yellow structure grows.ZusammenfassungWenn ein Stück einer flachen Aluminiumfolie mit einer Nadel in einer Allylchlorid/Toluol-Lösung angestochen wird, erscheint an diesem Punkt rasch ein rotgefÄrbter Fleck. Auf dem roten Fleck wÄchst kontinuierlich mit einer Geschwindigkeit von ungefÄhr 3 cm pro Std. ein leicht gelbes sackÄhnliches Produkt. Da dieses Produkt aus Polymeren besteht und einen definierten Wachstumspunkt wie den Keim einer Pflanze besitzt, könnte das Wachstum als noch besser passendes Modell eines biologischen Wachstums als die bisher bekannten Modelle angesehen werden (z. B. Traubes künstliche Zellen und chemische BlumengÄrten). Wenn man eine Linie mit einem Messer auf der Folie in der Lösung einritzt, so wird diese Linie rasch rot gefÄrbt, und ein dünnes plattenÄhnliches Produkt wÄchst auf der roten Linie. So kann jeder beliebige Buchstabe mit einem Messer auf der Aluminiumfolie so geschrieben werden wie mit einem roten Stift auf wei\em Papier. Anschlie\end wÄchst auf dem roten Buchstaben eine leicht gelbe Struktur.

Dissolution behavior of homologously generated surfactant molecular complexes (SMC) in aqueous media: A clue to the elucidation of the phenomenon "solubilization".

The solution behavior of homologously obtained crystalline surfactant molecular complexes (SMCs) that are generated between quaternary ammonium bromide and several additive materials has shed light on the recognition of fundamentals of solubilization. It has been revealed that the SMCs derived from long-alkyl-chain surfactants are sufficiently dissolved in water through the path of micellar dispersion above the cmcs of the complex surfactants, whereas the short-chain homologues cannot dissolve in water but dissociate the complexes, resulting in a heterogeneous phase made up of the liberated additives. The fact agrees perfectly with the familiar aspects of solubilization by surfactant; i.e., the longer the alkyl chain of the surfactant becomes, the more effective it is for solubilization. Based on these results, it has been deduced that the possibility for any pair of surfactant and solubilizate (additive) to realize solubilization simply depends on the relative importance of equilibrium of dissociation or association of the SMC species in aqueous medium.

The nuclear magnetic resonance spectrum of poly-N-vinylcarbazole

The n.m.r. spectrum of poly-N-vinylcarbazole is assigned and discussed on the basis of a polymer chain with restricted internal rotations.

Cationic polymerization of 9-vinylacridine

9-Vinylacridine (VAcr) was polymerized with ethyldichloroaluminium to give poly-9-vinylacridine (PVAcr).