Naslov
Lamellar/Inverted Hexagonal Phase Transition of 1,-(4)Dodecylbenzenesulphonate in mixed Water/Octanol/Electrolyte Media

Autori
Jalšenjak, Nenad ; Težak, Đurđica ; Hoffmann, Heinz ; Ulbricht, Werner ; Thunig, Christine ; Popović, Stanko

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
10th Conference of the European Colloid and Interface Society / Rosenholm, Jarl B. - : Abo Academie, 1996, P-II.06

Skup
10th Conference of the European Colloid and Interface Society

Mjesto i datum
Turku, Finska, 02.09.1996. - 06.09.1996

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
Lamellar/Inverted Hexagonal Phase Transition; Dodecylbenzenesulphonate

Sažetak
The investigation of mesophases in the ternary systems of sodium 1,-(4)-dodecylbenzenesulphonate(4SDBS)/water/Mg(NO3)2 in comparison to the binary system without Mg(NO3)2 showed an extension of the lamellar phase region towards lower concentration of surfactant, as well as the appearance of a three phase region of two isotropic phases and a lamellar one at higher temperatures. One of the isotropic phases may be pseudo isotropic and could be an oriented nematic phase. A transition of the lamellar phase to an inverse hexagonal one has been observed in water and n-octanol mixtures, above an octanol content highest than 30 weight percentage, by cooling the isotropic sample from 55 0C . The transformation of inverse hexagonal phase to the equilibrium lamellar one at room temperature showed a long relaxation time until two days. The formation of the liquid crystalline phase within one of the isotropic phases was also promoted either by shear or by cooling of the isotropic solution, i.e. either in the water phase at lower, and in the octanol phase at higher octanol contents, due to the solubility in the water and octanol phase, respectively. The X-ray diffraction measurements confirm the formation of lamellar phases in the aqueous solutions with a periodicity of a flat lamellar phase of 31.0 Ĺ for the 4SDBS/water/Mg(NO3)2 samples. In the samples 4SDBS/water/octanol/Mg(NO3)2 two peaks are observed, one of them belonging to the lamellar phase with a periodicity of 31.0-31.5 Ĺ. The other peak at 24.5 Ĺ could not be identified unambiguously with a certain liquid crystalline phase until now.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

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