A didodecyldimethylammonium bromide ternary system: Characterization of three-phase stable emulsions by optical microscopy

• A preliminary characterization of the didodecyldimethyl ammonium bromide (DDAB)/water (W)/per fluorooctane (PFO) ternary system at 25 degreesC is presented. The gradual addition of water, followed by mixing, to DDAB/PFO mixtures produces very stable emulsions for water contents greater than 20 wt%. On the basis of macroscopic observation, at least four different types of emulsions form up to a water content of around 97 wt%. On the basis of high conductivity values, a water-continuous domain is suggested at all compositions. A second phase diagram, considerably different in phase boundaries, is obtained by adding the PFO oil to DDAB/W samples. This allowed us to ascertain the swelling properties of L-alpha1 and L-alpha2 lamellar phases. Optical microscopy in the presence and in the absence of polarized light revealed the formation of lamellar liquid crystals either as randomly localized islands or as rings surrounding the oil droplets. Vesicles are identified at high water content. The contemporaneous presence of both L-alpha1 and L-alpha2 lamellar phases causes a synergistic effect in the PFO stabilization.

Ämnesord

NATURVETENSKAP  -- Kemi -- Fysikalisk kemi (hsv//swe)

NATURAL SCIENCES  -- Chemical Sciences -- Physical Chemistry (hsv//eng)

Nyckelord

three-phase emulsions

DDAB

optical microscopy

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