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Titolo:
PHASE-BEHAVIOR OF POLYOXYETHYLENE TRISILOXANE SURFACTANT IN WATER ANDWATER-OIL
Autore:
KUNIEDA H; TAOKA H; IWANAGA T; HARASHIMA A;
Indirizzi:
YOKOHAMA NATL UNIV,GRAD SCH ENGN,HODOGAYA KU,TOKIWADAI 79-5 YOKOHAMA KANAGAWA 240850 JAPAN NOEVIR CO LTD,BASIC RES LAB YOUKAICHI 5270057 JAPAN DOW CORNING TORAY SILICONE CO LTD ICHIHARA 29901 JAPAN
Titolo Testata:
Langmuir
fascicolo: 18, volume: 14, anno: 1998,
pagine: 5113 - 5120
SICI:
0743-7463(1998)14:18<5113:POPTSI>2.0.ZU;2-L
Fonte:
ISI
Lingua:
ENG
Soggetto:
QUARTZ-CRYSTAL MICROBALANCE; SILOXANE SURFACTANTS; NONIONIC SURFACTANTS; AQUEOUS-SOLUTIONS; SYSTEMS; MICROSTRUCTURE; AGGREGATION; MICELLES; SHAPE; HLB;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
35
Recensione:
Indirizzi per estratti:
Citazione:
H. Kunieda et al., "PHASE-BEHAVIOR OF POLYOXYETHYLENE TRISILOXANE SURFACTANT IN WATER ANDWATER-OIL", Langmuir, 14(18), 1998, pp. 5113-5120

Abstract

A phase diagram of the polyoxyethylene trisiloxane surfactant-water system was constructed as a function of polyoxyethylene (EO) chain length at 25 degrees C. The HLB (hydrophile-lipophile balance) of surfactant corresponds to the volume ratio of the EO chain to that of surfactant molecule (phi(EO)/phi(S)), where phi(S) and phi(EO) indicate the volume fractions of surfactant and hydrophilic moiety in the system, respectively. Aqueous micellar (Wm), hexagonal liquid crystalline (H-1), lamellar liquid crystalline (L alpha), and reverse micellar (Om) phases are formed with decreasing phi(EO)/phi(S). A sponge phase (D-2) is also formed near the L alpha phase region. The effective cross sectional area per one surfactant molecule, as, in liquid crystals in the present systems depends only on their EO chain lengths and are the same asthat in ordinary linear hydrocarbon surfactant systems. Since the maximum length of the trisiloxane moiety in its extended form is short, the L alpha phase is formed at phi(EO)/phi(S) between 0.45 and 0.6 in the present system, whereas an ordinary linear-type nonionic surfactantforms the H-1 phase in the same range of phi(EO)/phi(S). The H-1 phase, which was observed in a narrow range of phi(EO)/phi(S), becomes stable upon addition of oil. Although the H-1 phase in the absence of oilis considered to have the hexagonal structure confirmed by polarized optical microscopy, the calculated radius of the cylinder is much longer than the hydrophobic chain length in its extended form. Perhaps, the present H-1 phase is different from an ordinary hexagonal liquid crystalline structure. The three-phase behaviors of microemulsions in thepresent systems were also examined.

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Documento generato il 30/11/20 alle ore 09:53:17