ISSN:
1435-1536
Keywords:
Fluorocarbonsurfactant
;
mixedsystem
;
ion-pairedsurfactant
;
P β phase
;
lamellarphase
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract Two ternary phase diagrams of the cationic perfluorosurfactant diethanolheptadecafluoro-2-undecanolmethylammonium chloride (DEFUMAC) with an anionic perfluorosurfactant lithium perfluorooctanesulfonate (LiFOS) and an anionic hydrocarbon surfactant lithium dodecyl sulfate (LiDS) have been established at 25°C. The total surfactant concentration was less than 20wt%. In a wide mixing region of the LiFOS/DEFUMAC system, a lamellar-type phase,P β, was identified by its texture under a polarization microscope and by its x-ray diffraction pattern. Dispersed fragments ofP β-phase are present in the dilute solutions in which one surfactant was in excess. The anisotropy of electrical conductivity, flow birefringence, dynamic light scattering, and electric briefringence demonstrate that theP β fragments are disk-like with a radius of 0.7 μm. The disk-likeP β particles are transformed by shear into a spherical aggregate ofL α above a critical shear gradient. LiDS/DEFUMAC mixed solution forms dispersed and precipitatedL α in the dominant region. Radius and micropolarity of the dispersedL α aggregates are decreased as the ratio of LiDS:DEFUMAC approaches 1:1. On the basis of x-ray diffraction measurement the structure of precipitatedL α-phase seems to consist of monolayers.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00657733
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